Topicm75b4c6df2066b463_1528449000663_0Topic

Mental calculations – dividing natural numbers

Levelm75b4c6df2066b463_1528449084556_0Level

Second

Core curriculumm75b4c6df2066b463_1528449076687_0Core curriculum

II. Operations on natural numbers. The student:

3) multiplies and divides natural numbers by natural numbers, one‑digit, two‑digit or three‑digit with the long method, by doing mental calculations (in the easiest examples) and using the calculator (in more difficult examples).

Timingm75b4c6df2066b463_1528449068082_0Timing

45 minutes

General objectivem75b4c6df2066b463_1528449523725_0General objective

Performing simple calculations in memory or more difficult operations using the long methods, and applying this skills in practical situations.

Specific objectivesm75b4c6df2066b463_1528449552113_0Specific objectives

1. Appropriate using of the mathematical language to describe arithmetic operations.

2. Discovering some properties of the division.

3. Communicating in English, developing basic mathematical, computer and scientific competences, developing learning skills.

Learning outcomesm75b4c6df2066b463_1528450430307_0Learning outcomes

The student:

- uses appropriately the mathematical language to describe arithmetic operations,

- discovers some properties of the division.

Methodsm75b4c6df2066b463_1528449534267_0Methods

1. Situational analysis.

2. Task contest.

Forms of workm75b4c6df2066b463_1528449514617_0Forms of work

1. Individual work.

2. Group work.

Lesson stages

Introductionm75b4c6df2066b463_1528450127855_0Introduction

Students give examples of the division of natural numbers, while using the multiplication table.

Task
Individual work

Students work individually, using computers. Their task is to get to know the Interactive illustration, which describes the names of numbers we divide and the result of the division.

[Interactive illustration]

Procedurem75b4c6df2066b463_1528446435040_0Procedure

Group work

The teacher divides the class into three groups. Each group does the exercises from the worksheet, using calculators.

Worksheet for the group 1.

Task
See the following example.

[Illustration 1]

24:6=4,   because   4·6=24

Using the example, do the divisions and check them. Fill the dotted spaces:

a) 65 : 5 = ……., because ……………………………,

b) 48 : 3 = ……., because ……………………………,

c) 91 : 7 = ……., because ……………………………,

d) 84 : 6 = ……., because ……………………………

How can you check if the division was done correctly? Write down your answer.

Worksheet for group 2.

Task
Calculate:

a) 0 : 3,

b) 0 : 52,

c) 0 : 69,

d) 0 : 70.

The dividenddividenddividend is equal to 0. How much is the quotientquotientquotient? Write down the answer.

Worksheet for group 3.

Task
Calculate:

a) 25 : 1,

b) 365 : 1,

c) 486 : 1,

d) 5268 : 1.

The divisordivisordivisor is equal to 1. How much is the quotientquotientquotient? Write down the answer.

Worksheet for group 4.

Task
Calculate:

a) 25 : 25,

b) 365 : 365,

c) 486 : 486,

d) 5268 : 5268.

The divisordivisordivisor is equal to the dividenddividenddividend. How much is the quotientquotientquotient? Write down the answer.

Students present the results of their work. They draw conclusions.

The conclusions students should draw:

- We can check if the division was done correctly by doing the multiplication.
- If the dividend is equal to zero, then the quotient is also equal to zero.
- If the divisor is equal to one, then the quotient is equal to the dividend.
- If the divisor is equal to the dividend and is different than zero, then the quotient is equal to one.
m75b4c6df2066b463_1527752263647_0- We can check if the division was done correctly by doing the multiplication.
- If the dividend is equal to zero, then the quotient is also equal to zero.
- If the divisor is equal to one, then the quotient is equal to the dividend.
- If the divisor is equal to the dividend and is different than zero, then the quotient is equal to one.

Task contest.

Students do the operations, using the rules they learnt. They pass next levels of the contest, as they can only reach the next one once they do correctly examples from the previous level.

Three students with the best time get the highest marks, next three – second highest marks.

Task contest – level A
Write down, calculate and verify the solution:

a) the quotientquotientquotient of numbers 96 and 4,

b) the quotient of numbers 54 and 3,

c) the quotientquotientquotient of numbers 804 and 4,

d) the quotient of numbers 510 and 3.

Task contest – level B
Calculate using the example. Check if the solutions are correct.

Example:

48:12=48:2:6=24:6=4

a) 210 : 6,

b) 120 : 15,

c) 440 : 8.

Task contest – level C
Find numbers a, b, c, d:

a) 156 : a = 156,

b) b : 159 = 0,

c) 84 : c = 6,

d) d : 12 = 7.

Task contest – level D
Do the tasks. Write down solutions and verify them:

a) 180 yoghurts were packed into boxes, 15 in each box. How many boxes were used?

b) 96 DVDs were bought for the computer room, in 8 identical boxes. How many DVDs were in each box?

c) A string 80 m long was divided into 16 equal parts. What was the length of each one of them?

The teacher clarifies doubts and grades the groups’ work.

An extra task
Basia and Kasia are 14 years each and grandma Krysia is 86 years old. Calculate in how many years the girls will have as many years together as grandma is now.m75b4c6df2066b463_1527752256679_0Basia and Kasia are 14 years each and grandma Krysia is 86 years old. Calculate in how many years the girls will have as many years together as grandma is now.

Lesson summarym75b4c6df2066b463_1528450119332_0Lesson summary

Students do the revision exercises. Then together they sum‑up the classes, by formulating the conclusions to memorise.

- We can check if the division was done correctly by doing the multiplication.
- If the dividend is equal to zero, then the quotient is also equal to zero.
- If the divisor is equal to one, then the quotient is equal to the dividend.
- If the divisor is equal to the dividend and is different than zero, then the quotient is equal to one.
m75b4c6df2066b463_1527752263647_0- We can check if the division was done correctly by doing the multiplication.
- If the dividend is equal to zero, then the quotient is also equal to zero.
- If the divisor is equal to one, then the quotient is equal to the dividend.
- If the divisor is equal to the dividend and is different than zero, then the quotient is equal to one.

Selected words and expressions used in the lesson plan

dividenddividenddividend

divisordivisordivisor

elementelementelement

productproductproduct

quotientquotientquotient

quotient equal to onequotient equal to onequotient equal to one

verifying division with multiplicationverifying division with multiplicationverifying division with multiplication

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dividend 1
dividend

dzielna - liczba, którą dzielimy

RbhNh8zVDxri81
wymowa w języku angielskim: dividend
quotient 1
quotient

iloraz – wynik dzielenia

RaOUwEjXlN3jc1
wymowa w języku angielskim: quotient
divisor 1
divisor

dzielnik – liczba przez którą dzielimy

RDgMIpwWMXYWc1
wymowa w języku angielskim: divisor
element1
element

czynnik

RSpv80TXUz3Jx1
wymowa w języku angielskim: element
product1
product

iloczyn

R1LGPNV0IbgNj1
wymowa w języku angielskim: product
quotient equal to one1
quotient equal to one

iloraz równy jeden

R1MYNrsg1GaO91
wymowa w języku angielskim: quotient equal to one
verifying division with multiplication1
verifying division with multiplication

sprawdzanie dzielenia za pomocą mnożenia

RXCfuCAlvXF9j1
wymowa w języku angielskim: verifying division with multiplication