Nesterenko Galina Garisonovna
Job title: mathematic teacher
Educational institution: State public educational institution of the Krasnodar Territory special (correctional) school No. 27
Locality: g.c. Anapa
Material name: methodical development
Subject:"Addition and subtraction of round hundreds within 10000"
Publication date: 30.09.2018
Chapter: secondary education
Nesterenko Galina Garisonovna
Summary of the lesson of mathematics
in 6th grade
Teacher: Nesterenko Galina Garisonovna
Topic: "Addition and subtraction of round hundreds within
Lesson type: combined lesson
Correctional: to consolidate the skills of work according to verbal instructions,
develop connected and phrasal speech; develop and correct higher
mental processes in students; develop skills to use
past experience.
Educational: the formation of skills to add and subtract numbers
Educational: to cultivate curiosity, interest in lessons
mathematics.
Equipment: interactive whiteboard, cards, textbook.
Literature:
1) PROGRAMS of special (correctional) general education
institutions of the VIII type. Under the editorship of Voronkov V.V.
2) Mathematics. Textbook for grade 6 special (correctional)
educational institutions of the VIII type. Edited by
G.M. Kapustina, M.N. Perova.
3) METHODOLOGY of teaching in a correctional school. Edited by
Perovoi M.N.
Organizing time,
Purpose: to set up students to learn new
Objectives: to activate vocabulary with
writing multi-digit numbers and highlighting
bit units,
Develop cognitive activity
the basis of analysis operations when comparing
numbers. Activate counting skills
"Soft landing." Numbers messed up.
name them ok
increasing (1 group) 100,300, 700,
900,200,400,600,500,800.
(Group 2) 3,2,4,1,5.
A minute of reading. Find the missing word:
sum, term, reduced, term.
Verbal counting
The purpose of the second stage of the lesson is to prepare
students to learn addition and subtraction
round hundreds within 10000
Rhythm: once in a dense forest
The hedgehog built himself a house.
Invited forest animals
Count them quickly:
2 little fox, hare and funny teddy bear.
2 group: prescribe
numbers 1,2,3,4,5. Goal
: health promotion, physical development and
increase the efficiency of students;
Formation of correct posture skills in
static positions and in motion.
I.p. - sitting at the desk
1-2 tightly clenched their palms, bending their fingers.
3-4 relaxed. Repeat 3-4 times.
1-2 raised their hands up, palms are connected
(inhale) 3-4 - returned to I.p. (exhalation)
Repeat 3-4 times.
I.p. sitting hands on the belt 1- swing left hand
sweep over the right shoulder, turn your head
to the left, 2 - i.p. 3-4 - the same with the right hand.
Repeat 4-5 times.
The pace is slow.
Learning a new curriculum
material.
The purpose of the third stage of the lesson
developing the ability to fold and
Correctional: the formation of skills
use past experience, consolidate skills
work according to verbal instructions, develop
Tutorial: shaping computed
Educational: cultivate perseverance.
200+300= 200+300+100=
We need to buy bread
Ile gifts to give
We take the bag with you
And we go to the street
There we pass along the windows
And we go to the store.
The game "Let's go to the store." slide 1
hat-200r.
Sneakers-600r.
Boots-300r.
How much is the hat and scarf? How much are
boots and scarf? How much is the hat and
sneakers? How much is the hat and boots?
Pencil-1r.
Notebook3r.
How much do pen and pencil cost?
How much do a notebook and pencil cost?
Consolidation of educational
material.
Purpose: to check how students have learned a new
material;
Educational tasks:
Continue developing folding skills
Corrective tasks:
Develop students' ability to identify
the main thing in the studied material is to work on
verbal instruction.
Let's check how we learned addition and subtraction
four digit numbers.
Do your own work. Group
Level 1 students learning opportunities.
1)200+300 2)500+100
3)200+300+100 4)600 +200+100
learning.
Write 1,2,3,4,5.
Help available in case of difficulty
round hundreds within 1000. - How to add
or subtract round hundreds within 1000?
Homework assignment.
Strengthen addition and subtraction skills
round hundreds within 1000.
Develop memory based on memorization of rules,
reinforce verbal skills
instructions, reinforce addition skills and
subtraction of four-digit numbers. Bring up
autonomy, mindfulness.
Opportunity Level 1 Student Group
training: p. 50#201 (1).
Group of students of the 2nd level of opportunity
training: p. 50 No. 201 (1) 1,2 column ..
Group of 3rd Opportunity Students
training: p. No. 201 (1) 1 column.
Learn the rules: p.50.
Lesson
ADDITION AND SUBTRACTION OF ROUND Hundreds
Pedagogical tasks :
educational: create conditions for fixing the computational skills of adding and subtracting numbers with the transition through the category within 100,introduce the algorithm for adding and subtracting round hundreds;
correctional-developing: promote the development of mental operations, coherent speech of students,
educational: promotein complianceaccuracy in the design of notes in notebooks.
Expected (planned) results:
Subject: learn how to add and subtract round hundreds; learn to apply this rule when solving examples.
Cognitive: learn to build a speech statement in oral form.
Regulatory: learn how to control step by stepToresult.
Communicative: learn to ask questions.
Personal: will have the opportunity to form a sustainable educational and cognitive interest in new general ways of solving problems.
Equipment: textbook mathematics grade 5 author Perova M. N. and Kapustina G. M.,visualmaterialFororalaccounts;supports;workingnotebookBymathematics;abacus;cardsForindividualwork.
During the classes
I. Organizational moment
Greetings. Examination readiness To lesson. Emotional mood .
The teacher reads a poem.
Addition is a very, very simple operation:
Let's put all kinds of things together.
Put the toys in a box or in a wrapper box ...
And you will become real great mathematicians.
Anyone who wants to be friends with numbers can easily add everything himself!
A. Usachev
– What do you think the topic of the lesson is?(Addition of numbers.)
– Name the inverse of addition.(Subtraction.)
– Today in the lesson we will learn how to add and subtract numbers within 1000.
Students open notebooks, write down the number, class work.
II. Verbal counting.
1. Exercise "Insert the missing numbers."
7 + … = 15 12 – … = 7
8 + … = 14 … – 8 = 6
… + 9 = 16 15 – … = 9
– What are the names of the components when added together?(First term, second term, sum.)
– What are the subtraction components called?(Reduced, subtracted, difference.)
– How to find the unknown term?(To find the unknown term, subtract the known term from the sum.)
– What should be done to find the unknown minuend, subtrahend?(To find the unknown minuend, you need to add the subtrahend to the difference. To find the unknown subtrahend, you need to subtract the difference from the minuend.)
2. Exercise "Fill in the table."
The teacher shows the table.
term
18
3
13
term
11
4
18
Sum
15
17
Minuend
14
17
18
Subtrahend
3
9
7
Difference
8
3
– What arithmetic operations with numbers did you perform?(Addition, subtraction.)
– Within what bit unit were numbers added and subtracted?(Within 100.)
III. Actualization of the sensory experience of students.
– What class did you study?(Class of units.)
– WhichranksconstituteClassunits?(Units, tens, hundreds.)
– On which wire of accounts the units are deposited; tens; hundreds?(Units are laid on the first wire from the bottom; tens - on the second from the bottom; hundreds - on the third from the bottom.)
– Put the numbers on the abacus and write them in a notebook in two columns.
20 200
40 400
30 300
– What two groups according to the number of digits were they divided into?(Two and three digit numbers.)
– Read two digit numbers.(20, 40, 30.)
– What grade are they missing?(Units.)
– What are these numbers called?(Round tens.)
– What are the numbers in the second column called?(Round hundreds.)
– Prove it.(Ones and tens are missing, we write zeros in their place.)
– Make up three addition and subtraction examples from the numbers in the first column.(20 + 40; 40 – 20; 20 + 30; 30 – 20; 30 + 40; 40 – 30.)
– Solve them by explaining your solution.
– How to add, subtract round tens?(Round tens are added and subtracted in the same way as simple units.)
IV. Learning new material.
– Today we will learn how to add and subtract round hundreds.
– What arithmetic operation examples?(For addition.)
–
– How are round hundreds subtracted?
Conducting a physical minute
V. Correction and primary consolidation of knowledge.
Textbook work: fulfillment of tasks 110 (1, 2 st.), 114 (2, 3 st.) on p. 54–55.
students come out To blackboard By alone decide examples With explanation.
– Solve examples.
100 + 300 600 + 400 100 + 400 + 200
500 + 300 700 + 300 300 + 400 + 300
– How are round hundreds added up?
– Solve examples according to the model.
Sample: 50 – 30 = ?; 5 dec. - 3 dec. = 2 dec. = 20.
600 - 400 = ?; 6 hundred. - 4 hundred. = 2 hundred. = 200.
90 – 60 700 – 300
60 – 30 500 – 400 (The problem is about a train.)
– How can I write a brief condition of the problem?(The condition is drawn up in the form of a drawing.)
– How do you think the problem should be solved?(The action of addition.)
– Solve the problem yourself.
One student completes the task from the back of the board; examination.
– How are round hundreds added up?(Same as simple units and round hundreds.)
– Name the rules for crossing railroad tracks.(Student answers.)
VII. Summary of the lesson.
– What numbers did you learn to add and subtract?(Round hundreds.)
– How do you add and subtract round hundreds?(Round hundreds are added and subtracted in the same way as ones and round tens.)
– What class do round hundreds belong to?(Round hundreds are in the units class.)
– What numbers are called terms?(Numbers that add up are called terms.)
– What is the number to be reduced?(The number from which we subtract is called the minuend.)
– What is the subtracted number?(The number that is subtracted is called the subtrahend.)
Homework: task 110 (3, 4 pages), p. 54.
In the study of the operations of addition and subtraction within 1000, the following stages can be distinguished:
I. Addition and subtraction without crossing the category (oral).
1. Addition and subtraction of round hundreds. 192
200+100 300+200
Actions are performed on the basis of knowledge of numbering and are reduced to actions within 10. Reasoning is carried out 200 is 2 hundreds, 100 is 1 hundred.
This is 300. 200+100=300
Sot. + 1 cell = 3 cells. 3 hundreds
500-200=?
5 cells-2 cells=3 cells=300
Individual students who still need to use visual aids can be offered bunches of sticks (1000 "darlings, tied in bunches of a hundred), plates from an arithmetic box, strips 1 m long, each divided into 100 cm, n"> ak, abacus.
It is useful to solve and compose triples of examples of the form
| subsequent comparison of the components and results of actions.
2. Addition and subtraction of round hundreds and units, round
< отен и десятков (действия основываются на знании нумерации):
a) 300+ 5 305- 5 b) 300+ 40 340- 40
5+300 305-300 40+300 340-300
c) 300+ 45 345- 45
3. Addition and subtraction of round tens, as well as round
with otens and tens:
B) 430+200 630-200
When solving cases a), b), the reasoning is carried out as follows: “430 is 4 hundred. and 3 dec., 20 is 2 dec. We add tens: 3 dec. + 2 dec. = 5 dec. 4 hundred + 5 dec = 450.
The digits that are added or subtracted can be recommended to underline:
430+200=630 630-200=430
7 Perova M.N.
When solving examples of the form c) reasoning is carried out m|| “120 = 100 + 20, 430 + 100 = 530, 530 + 20 = 550”, i.e. this case (of addition (subtraction) is reduced to the addition (subtraction) teas already known to students a), b).
4. Addition of three-digit numbers with one-digit, two-digit | three-digit without passing through the discharge and the corresponding cases of subtraction:
| a) 540+5 543+2 | 545-5 545-2 | b) 545+40 585-40 | c) 350+23 356+23 | 373-23 379-23 |
| d) 350+123 | 673-123 | |||
| 356+123 | 679-123 |
Actions are performed verbally. When performing actions, students use the same techniques that they used when studying the actions of addition and subtraction within limits! 100, i.e., decompose the second component of the action (the second term -; mine or subtracted) into bit units and sequentially add or subtract them from the first component.
For example:
123=100+20+3 350+100=450 450+ 20=470 470+ 3=473
5. Special cases of addition and subtraction. These include 1 cases that cause the most difficulties and in which] errors are most often made. Students find it most difficult to work with zero (zero is in the middle of the number or at the end). The case with numbers containing zero does not require special tricks. But such examples need to be solved more, before solving such examples, repeat the solution of examples for addition and subtraction, when the action component is zero: 0+3, 5+0, 5-5:
A) 308+121 b) 402-201 V) 736-504
308+100=408 402-200=202 736-500=236
408+ 20=428 202- 1=201 236- 4=232
428+ 1=429
d) 0+436 700-0 725-725
x "intrinsic methods of calculation require students to have a constant shza of numbers according to their decimal composition, understanding the place of ra in a number, understanding that actions can be performed on digits of the same name. Not all students of an auxiliary school understand this at the same time. Before performing actions, it is necessary to seek from the student a preliminary analysis of the decimal composition of numbers. Learn-i-p. more often should raise questions: “Where should we start with complex-|pm"> What digits do we add?
Otherwise, students make mistakes in their calculations. They add tens with hundreds, and the result is written "|C)0 in the hundreds place, or in the tens place, for example: 100+10=500, 30+400=70, 30+400=470, 30+400=340, ( ./0+2=690, 670-3=640.
These errors indicate a misunderstanding of the positional meaning of the numbers in a number, an inability to independently control the results of actions. The teacher needs to ensure that students check the performance of actions, and they do this not formally, but in essence. It is not uncommon to observe that the student allegedly made the check, but carried it out formally. He wrote only the reverse action, but did not solve it, therefore he did not notice the mistake made, for example: 490-280=110. Examination. 110+280=490.
Often, mentally retarded schoolchildren (even high school students) may not understand the essence of verification. Checking is often performed by students only because it is either required by the teacher or such an assignment is contained in the textbook. Often, when performing a check, the student receives a discrepancy between the result obtained and the given example, but this does not serve as a reason for him to correct the wrong answer, for example: 570-150=320. Examination. 320+150=470.
In this case, the check acts as an independent action, in no way connected with the one that the student checks.
The teacher must constantly remember these mistakes of students with intellectual disabilities and demand answers to the questions: “What did the test show? Is the example correct? How to prove that the action is performed correctly?
The conscious performance of oral calculations, the development of generalized ways of performing actions is the constant attention
to questions of comparison and comparison of different cases of addition, subtraction. It is important to teach students how to look | the general and the particular in the examples they solve.
For example, compare examples and explain their solution:
30+5, 300+40, 300+45, 300+140, 300+145, 300+105.
305-5, 340-40, 345-45, 340-300, 345-300, 345-200.
It is also useful for students to compile examples that are similar (r similar) to data, or examples of a certain type: “Make it up! an example in which you need to add round hundreds with units";! “Make an example of subtraction, in which the minuend is | three-digit number, and the subtrahend is round tens ”, etc. 1
To fix the actions of addition and subtraction within the limit "1000 methods of oral calculations, it is useful to solve examples with | unknown components.
II. Addition and subtraction with transition through) category.
Addition and subtraction with the transition through the discharge - this is the most «| more difficult material. Therefore, students perform the actions of the column. Addition and subtraction in a column are made over each | smoke by discharge separately and are reduced to addition and subtraction within 20. But in this case, mentally retarded schoolchildren have difficulties in writing numbers, that is, in the ability to correctly sign the category under the corresponding category.
Often, due to the inability to organize attention, due to an insufficiently clear understanding of the positional meaning of the numbers in a number, or even due to negligence when writing numbers, students shift the number to be added or subtracted to the left or right, and therefore allowable; there are errors in the calculations. Students make especially many mistakes when writing numbers in a column, if the action is performed on a three-digit and two-digit or single-digit number. In this case, tens are signed by hundreds, units by hundreds or tens. This leads to errors in the calculations.
For example:
+ 6 + 38 ~18
The greatest difficulty is caused by the action of subtraction. Errors in calculations are of a different nature. The reason for some of
Poor students are allowed to perform all cases in the table
Their is poor mastery of tabular addition and subtraction
I within 20.
7 ~ 7
Many mistakes are made as a result of students
decrease to add a ten or a hundred that has turned out in the mind, and
They also forget that they "occupied" a hundred or ten. For example:
. 178 345
_____ "218
Especially difficult are the cases in which: 1) the transition through the discharge occurs in two discharges; 2) it turns out zero in one of the bits; 3) the minuend contains zero; 4) there is one in the middle of the minuend. For example:
"-" s? to the checkpoint
546 ~287 ~36T
-^tu^- -tge- or
Often, when subtracting, one can also encounter such a mistake: instead of “occupying” a unit of the highest category, splitting it up, the student begins to subtract from the larger digit of the subtracted smaller digit of the corresponding digit of the reduced one. For example:"
^___ 8 ~145
At the same time, the reasoning is carried out as follows: “From 5 units, 8 units cannot be subtracted; we subtract from 8 units 5, 7 tens and 3 hundreds
we demolish, the difference is 373.
Considering the difficulties of studying this topic, it is necessary to repeat addition and subtraction with students with the transition through the category within 20 and 100, pay attention to solving examples in which the component is zero, or zero is obtained
in one of the digits of the sum or __________, _______: _____________
difference (17 + 3, 25 + 15, 36-6, 36-27), or zero is contained in one of the digits of the reduced or subtracted (60-45, 75-40).
To those students who do not master the record for a long time! examples in a column, you can allow them to be written in a discharge) grid.
When solving examples for addition and subtraction with the transition through the discharge, the following sequence is observed:
1) addition and subtraction with the transition through the discharge in one discharge (units or tens):
| For example: | ||||
| .1010 | ||||
| ~375 | ~375 | ~805 | ~805 | ~1000 |
| 148 | ||||
| ~229" | G39~ | ~T68~ |
The solution of examples of the form 800--236, 810-236, 810-206 deserves special attention. It is necessary to compare first the 1st and 2nd, and then the 2nd and 3rd examples, the features of their solution, explain what their difference is, why different answers are obtained.
2) addition and subtraction with the transition through the discharge into two
digits (ones and tens): 375+486, 375-186, 286+58, 375-™
-86;
3) special cases of addition and subtraction, when in the sum or in
difference, one or two zeros are obtained when in the reduced
contains one or two zeros when the minuend contains
zero and one:
4) subtraction of three-digit, two-digit and one-digit numbers from 1000: 1000-375, 1000-75, 1000-5.
When explaining the solution of examples with the transition through the category, given that mentally retarded students forget to add the number that needs to be remembered when adding, you can be allowed to write this number over the corresponding category.
For example:
When subtracting, a dot is placed over the category from which the unit was taken. You can also put the number 10, which is written above the category, to the units of which this ten is added.
When performing operations on addition and subtraction within 1000, examples with three components without brackets and with parentheses are solved: 375+36+124; 379+(542-276); 910-375--264, 375+186-264, 1000-565+136. Examples are also solved for finding unknown components of actions. The check is performed in two steps.
Multiplication and division within 1000
Multiplication and division, as well as addition and subtraction, can be performed both by oral and written methods of calculation, written in a line and a column.
I. Verbal multiplication and division within 1000.
1. Multiplication and division of round hundreds.
Multiplication and division of round hundreds is based on students' knowledge of numbering, as well as tabular multiplication and division. Therefore, before introducing students to the multiplication and division of round hundreds, it is necessary to repeat tabular multiplication and division, as well as splitting hundreds into units and vice versa. For example: “How much does 1 hundred units contain? How many units are there in 5, 7, 10 hundreds? How many hundreds are 300 units? 500 units? And so on. The explanation of multiplication and division must be
guided by operations with visual aids and didactic || material.
Let's show an explanation of multiplication, and then division.
For example, you need 200-2. We reason like this: 200 is 2 hundred |
Let's take 2 hundred sticks and another 2 hundred sticks. There will be 4 hundred!
or 400. Let's write: 2 cells-2=4 cells=400, 200-2=400. ?,
When dividing 200:2, we argue like this: 200 is 2 hundreds. WHO! meme 2 hundred sticks. If you divide them into two equal parts, -t in each part you get one hundred, or 100 units. We write: 2 hundred: 2 \u003d 1 hundred. = 100, 200:2=100. Usefully compare, multiply and divide units, tens and hundreds:
tsitkov). Divide 18 tens by 3. We get 6 tens, or 60. Shim: 18 dess. :3=6 dec. =60, 180:3=60". The division process; but show both on sticks and on bars. First, students g. a detailed record, replacing units with tens, then the record _! Rip. Students are required to provide oral explanations. [and finally, curled up and explanation. Students only write
The same explanation is carried out when getting acquainted with the multiplication and division of round tens by a single digit. The solution of such cases is reduced to out-of-table multiplication and |and addition. Therefore, we give only a detailed record of the solution:
12 dec. -4 dec=48 dec=480 120-4=480
48 dec:4= 12 dec= 120 480:4=120
 |
The operations of multiplication and division must be compared, checking each with an inverse action: 400x2=800, 800:2=400.
2. Multiplication and division of round tens by a single digit.
a) The cases of multiplication and division of round numbers are considered.
syatkov, which are reduced to tabular multiplication and division:
60-3, 180:3. |
b) We consider cases that are reduced to non-table |
multiplication and division without crossing the category: 120-3, 480:4.
Before multiplying and dividing round tens with students, it is necessary to repeat tabular and extra-table multiplication and division (4-6, 24-2, 36:6, 36:3), as well as determining the total number of tens in the number (“How many tens are there in the number 120 , 180, 360, 720?") and the number of ones in tens ("7 tens. How many ones?"; "How many ones in 2 tens? 5 tens? 10 tens? 52 tens?").
When explaining, the following reasoning is carried out: “60-3=? 60 is 6 tens, 6 dec.-3=18 dec. 18 tens is 180, so 60-3=180. You can show students on the bars of the arithmetic box, bunches of sticks, connected by tens, that the result will be the same. To do this, the teacher takes 6 bars 3 times. Gets 18 bars, or 18 tens. This number is 180.
When getting acquainted with the division, the course of reasoning is similar: “180: 3 \u003d? Find out how many tens are contained in the number 180 (18,200
123-3=?_________
123 = 100+20+3 100-3=300 20-3= 60 3-3= 9 300+60+9=369
123=100+20+3 100-3=300 20-3= 60 3-3= 9 300+60+9=369
486:2 = ?_
486=400+80+6 400:2=200 80:2= 40 6:2= 3 200+40+3=243
100-3=300 20-3= 60 3-3= 9 300+60+9=369
4. Multiply 10 and 100, multiply by 10 and 100.
Within 1000, multiplication of a single-digit two-digit number by 10 and 100 and the corresponding cases of division * are considered:
8-100=800
| 10- 3 | 3- 10 | 80: 10 |
| 100- 8 | 8-100 | 800:100 |
| 25-100 | Yu-25 | 250: 10 |
The teacher explains the multiplication of the number 10, based on the concept of multiplication as the addition of equal numbers.
10-3=10+10+10=30 10-3=30
10-5=10+10+10+10+10=50 10-5=50
Several more examples are being considered. The answers are compared. Students make sure that when multiplying the number 10 by any factor, zero is assigned to it on the right.
Then, examples are solved for multiplying a single-digit number nya 10. The solution of the example 3x10=? is also performed by replacing multiplication with addition of identical terms:
3-10=3+3+3. . .+3=30 10 times
1 You can also use the commutative law of multiplication: \
Having considered a number of such examples, comparing the products and the first factor, students come to the conclusion: in order to multiply a number by 10, you need to add one zero to the right of the first factor.
This rule for multiplying a number by 10 also applies to multiplying two-digit numbers (25x10=250).
When multiplied by 100, the factor 100 is considered as the product of two numbers: 100=10*10. Students practically get acquainted with the use of the associative law of multiplication, although they do not name or formulate this law. The teacher explains: “In order to multiply a number by 100, you must first multiply it by 10, .. then multiply the product again by 10, since 100=10.10.”
Then the entry is given in the line: 6-100=6-10 10=600.
A few more examples are also solved in detail. When deciding - "and each example, the teacher asks to compare the product and the first factor. Students independently come to the conclusion: if you multiply a number by 100, you need to add zero to it on the right.
Multiplication of 100 by a single digit is done by using
using the commutative law of multiplication:
5. Targeting 10 and 100.
Division by 10, as experience shows, is better absorbed by students when compared with the action of multiplication. A division by 10 is treated as a division by content:
2-10=20, hence 20:10=2.
20:10=2 is followed by the question, "How many times is there one ten in two tens?"
As in multiplication, several examples are solved for dividing by 10, and the quotient and dividend are compared. Students make sure [ that in the quotient the dividend is obtained without one zero, and conclude:
To divide a number by 10, you must discard the zero on the right. This conclusion extends to dividing round hundreds and tens by 10 (400:10=40, 250:10=25).
Similarly, students are introduced to dividing by 100: 400:100=? 4-100=400 400:100=4
Dividing by 100 can also be explained by successively dividing by 10 and again by 10:
400:100=400:10:10=4
Students learn to divide by 10 and 100 both without a remainder and with a remainder: 40:10=4, 45:10=4 (remaining 5).
It should be pointed out that when dividing a number by 10 (100), it is determined how many tens (hundreds) are contained in it. Teach, it is necessary to remember that mentally retarded schoolchildren work to differentiate similar and opposite concepts || Therefore, when the students got acquainted with the rules of multiplying the division of a number by 10, 100, it is necessary to consider cases | which these rules are used simultaneously, who are asked to compare them, find similarities and differences:
40: 10 400: 10 400:100
It is also necessary to compare multiplication by 10 and 100 with
division by 1 and 0, division by 10, 100 divided by 1. This allows!
analyze expressions each time before proceeding!
performing an action.
A multiple comparison also helps to consolidate the action! numbers (how many times one number is greater or less than another).; For example, the following tasks are given: “How many times is 2 less than / 20, 200?”; "How many times is 300 more than 3, 10, 100?" An example of 300:3=100 can be read like this: "The number 300 is 100 times greater than 3." Or: "The number 3 is 100 times less than 300." “What actions can compare the numbers 400 and 10?” the teacher asks. The students answer: "You can compare these numbers by dividing and subtracting: 400:10, 400-10." Students learn to ask questions on their own: “How much more is 400 than 10?”; "How many times is 400 greater than 10?"
MAOU "Omutinsk special school"
Open math lesson in grade 5:
"Addition and Subtraction of Round Hundreds"
Mathematics teacher of the highest category: Usova G.P.
2014/15 academic year
Target:
to continue work on fixing the decimal composition of numbers from 100 to 1000 and the skills of adding and subtracting round hundreds and tens when solving problems and examples;
correction and developmentcognitive activity, skillsobserve, compare, classify, analyze and generalize;
Rdevelop mental processes: memory, attention, thinking;
create conditions for the psychological comfort of each child;
develop reflection and adequate self-assessment of their own activities in children;
to cultivate a culture of behavior in the classroom, interest in the subject, communication skills
DURING THE CLASSES
Organizing time
"Soft landing" Name the tens and units of the number: 42, 21, 35, 86, 918.64
We are attentive
We are diligent
We can do this!
A minute of reading.
Find an extra word, give a name to the group:
Ind work Makarov M
Work in notebooks.
Mathematical dictation
Write down the numbers from dictation: 800,155,400,321,500
Set aside on accounts: 512, 700, 200, 139
Divide into 2 groups, give names (justify your answer)
Write off the numbers: 70,23,45,80,60,10,38,15.
II. Verbal counting
1) Rhymes+ - (attention task)
2) Tasks in verse
Grandmother Nadia lives in the village.
He has animals, but does not keep score.
I will call them guys
And you try to quickly count:
Cow, calf, two gray geese,
Sheep, piglet and cat Katusya.
How many animals does Grandma Nadia have in total? (7)
3) Insert the desired character
30…20 =50
90…30=60
50…40=10
700…100=80
800…200=1000
Ind work Makarov M
Working with accounts:
5+1= 6 - 4= 4+3= 8 - 3=
II I Knowledge update (setting the goals of the lesson) - we will add and subtract round hundreds
200+300= 500+100= 200+300+100= 600+200+100=
Why do you need to know how to add and subtract numbers?
Where in your life have you seen round three-digit numbers?(On banknotes) 100, 500, 1000 rubles
Mystery.
We need to buy bread
Ile gift to give -
We take the bag with you
And we go to the street
There we pass along the windows
And we go to...
Game "Let's go to the store."
Tasks on cards
Hat -200r.
Boots -600r.
Sneakers -500r.
T-shirt -400r.
Skirt -300r.
Pants -700r.
Gloves -100 rub.
Ind work Makarov M
Handle-3r.
Pencil - 1p.
Notebook -5r.
Purchase cost 3+1+5=
IV Fizkultminutka
1) The teacher says the following words: “hundreds”, “tens”, “units”. Students stand and use their hands to show: hundreds - hands are closed above their heads in the form of a large triangle, tens - thumbs and forefingers are connected in pairs, forming a small triangle, units - the work of hands on a computer keyboard on the table is imitated.
2) Relaxation with eyes closed (imagining objects in the classroom)
V. Work on the topic
Open the textbook on page 54, Find the task under the number, which is deferred on the accounts 112
The solution of the problem.
P.54 №112
Questions :
– Break the condition into semantic parts.
- Repeat the question.
Can you answer the question right away?
– Is there one action in the task? Two? Three? Why? Prove it.(Two data, unknowns too 2.)
Change the question so that the task is solved in 1 step.
100kn.+200kn.=300kn.-on the second day
100kn.+300kn.=400kn. – in 2 days
V I . Anchoring
What are numbers called when added?
500+ 100
500+200
500+300
How are the examples similar?
Decide, compare the sums, draw a conclusion.
VI I . Independent work
№110
№117 (Procedure) Khrapin V., Ind. Assignment Makarov M (grade 2)
VI II . Summary of the lesson. Reflection
The wind plays with leaves
picks them off the trees.
Everywhere the leaves are circling -
this means...(Leaf fall)
Orange – I understand everything, I am satisfied with my work.
Yellow - can work better
Green - it was difficult for me
Lesson 77
adding round hundreds
Goals: learn how to add "round" hundreds; improve computing skills; to form the ability to solve text problems; to consolidate the ability to compose a numerical expression for a drawing; develop logical thinking and attention.
During the classes
I. Organizational moment.
II. Verbal counting.
1. Guess what rule the schemes are drawn up by, insert the numbers into the "windows".
2. Put the signs "+" or "-".
69 … 40 … 8 = 21 17 … 70 … 2 = 89
75 … 5 … 30 + 40 31 … 60 … 7 = 98
20 … 6 … 2 = 24 61 … 8 … 9 = 60
8 … 2 … 47 = 57 34 … 4 … 6 = 36
3. Task.
In three days the workers repaired 24 trolleybuses: on the first day 8 trolleybuses, on the second day 10. How many trolleybuses did they repair on the third day?
III. The topic of the lesson.
- Read the numerical expressions.
| 400 + 500 |
||
| 200 + 400 | ||
– Find the “extra” expression in each column.
- Today in the lesson we will learn how to add "round" hundreds.
IV. Work on the topic of the lesson.
1. Task 1.
- Read the problem.
- What is known?
- What do you need to know?
- Solve the problem.
Red - 3 hundred. onion.
Yellow - 2 hundred. onion.
Total - ?
3 hundred. + 2 hundred. = 5 hundred. (bulbs) - total.
Answer: 5 hundred. bulbs.
How do you add hundreds?
2. Task 2.
Students add hundreds.
5 hundred. + 4 hundred. = 9 cells. 4 hundred. + 3 hundred. = 7 hundred.
7 hundred. + 1 hundred. = 8 hundred. 5 hundred. + 5 hundred. = 10 hundred.
3. Task 3.
- Write each given number of hundreds as "round" hundreds.
1 hundred = 100 8 cells. = 800
2 hundred. = 200 7 hundred. = 700
5 hundred. = 500 3 hundred. = 300
4 hundred. = 400 6 cells. = 600
4. Task 4.
- Read the problem.
- Compare it with task 1. How are they similar? What is the difference?
- Solve the problem.
Red - 300 onions.
Yellow - 200 onions.
Total - ? onion.
300 + 200 = 500 (bulbs) - total.
Answer: 500 bulbs.
Physical education minute
5. Task 5.
– Add round hundreds.
- Why is it that when adding "round" hundreds, a number is obtained that is a "round" hundred?
6. Task 7.
How many big red squares? (3.)
How many big blue squares? (1.)
How many squares is each large square divided into? (At 100.)
How many red cells are there? (3 cells = 300.)
How many blue cells are there? (1 hundred = 100.)
- How many cells are there?
- Make a numerical equation according to this picture.
V. Summary of the lesson.
- What did you learn at the lesson?
- How to perform the addition of "round" hundreds?
Homework: textbook, p. 12, no. 6.
Lesson 78
subtraction of "round" hundreds
Lesson Objectives: learn how to subtract "round" hundreds; improve computing skills; to form the ability to solve text problems; to consolidate the ability to compare the values of numerical expressions; develop logical thinking.
During the classes
I. Organizational moment.
II. Verbal counting.
1. Guess what numbers you need to insert into the "windows".
2. Solve the rules and continue the rows of numbers:
a) 13, 15, 19, 25, 33, ..., ..., ...;
b) 81, 84, 80, 83, 79, ... , ... , ... ;
c) 9, 12, 16, 21, 27, 34, ..., ..., ....
3. Task.
Vasya drew a three-story house. On the ground floor, he painted doors and 6 windows, and on the top two floors, 8 windows each. How many windows did Vasya draw in this house?
4. In each line, instead of dots, insert the missing figures, keeping the order of their alternation.
III. The topic of the lesson.
- Consider numerical expressions.
| 8 dec. - 2 dec. | ||
| 9 hundred. - 3 hundred. | ||
| 7 dec. - 5 dec. | 800 – 600 |
- In each column, find the "extra" numerical expression.
– Today in the lesson we will learn how to subtract “round” hundreds.
IV. Work on the topic of the lesson.
1. Task 1.
- Read the problem.
- Solve the problem.
3 hundred. - 1 hundred. = 2 hundred. (feast) - baked by the 2nd bakery.
Answer: 2 hundred. pies.
2. Task 2.
- Subtract hundreds.
7 hundred. - 2 hundred. = 5 hundred. 9 hundred. - 3 hundred. = 6 hundred.
5 hundred. - 4 hundred. = 1 hundred. 6 hundred. - 1 hundred. = 5 hundred.
3. Task 3.
- Read the problem.
- What is known? What do you need to know?
– Compare tasks 1 and 3. How are they similar?
- Solve this problem.
300 - 100 = 200 (pyr.) - baked by the 2nd bakery.
Answer: 200 pies.
Physical education minute
4. Task 5.
- Draw up an expression.
( + ) –
- Solve these numerical expressions.
(300 + 200) – 200 = 500 – 200 = 300
(500 + 300) – 100 = 800 – 100 = 700
(400 + 500) – 300 = 900 – 300 = 600
(600 + 300) – 500 = 900 – 500 = 400
(200 + 400) – 400 = 600 – 400 = 200
(300 + 400) – 600 = 700 – 600 = 100
5. Task 6.
How are these numerical expressions similar?
- What should be done first?
- Draw up an expression.
– ( + )
– Carry out the indicated steps.
500 – (200 + 200) = 500 – 400 = 100
700 – (400 + 300) = 700 – 700 = 0
800 – (200 + 400) = 800 – 600 = 200
900 – (500 + 300) = 900 – 800 = 100
6. Task 7.
– Compare the values of numerical expressions. Write the comparison results in the form of true equalities or inequalities.
600 – 200 600 – 300
700 – 200 = 700 – 100 – 100
(500 + 400) – 100 = 900 – 100
800 – (100 + 600)
What knowledge helped you complete this task?
V. Summary of the lesson.
- What did you learn at the lesson?
- How to subtract "round" hundreds?
Homework: textbook, p. 14, no. 4.
