Division

Objectives

To divide a 2 or 3 digit number by a 1 digit number by ‘chunking’.

To understand the connection between division and multiplication.

Resources

Abacus 4 Textbook 2 | Squared paper | Division with Chunking (YouTube)

Today's Lesson

Main Activity

Turn to page 40 in Abacus 4 Textbook 2.

Remind your student of the chunking method of division, where ‘chunks’ of numbers are taken away from the number to be divided, so that it becomes more manageable. We usually start by multiplying the dividing number (the divisor) by 10 as this is an easy calculation to do. This answer is then subtracted from the larger number, until the result is within the times table of the divisor. Then the chunks of the divisor are added together.

For example:

95 ÷ 5 =

We would first find a large chunk to take away from the 95 by multiplying 5 by 10.

10 x 5 = 50

We set out the calculation as below:


	95
(10 x 5)	-50
	45
(9 x 5)	-45
	0

Now add the 10 and the 9 together (the 2 numbers you multiplied by 5 - the divisor - to find the ‘chunks’).

10 + 9 = 19

Therefore, 95 ÷ 5 = 19

This method can also be used for much larger numbers, where you may have to multiply by 10 more than once, and there can be remainders. For example:

147 ÷ 6 =


	1 4 7
(10 x 6)	- 6 0
	87
(10 x 6)	- 6 0
	2 7
(4 x 6)	- 2 4
	3

Add the number of groups together: 10 + 10 + 4 = 24

We have a remainder of 3 at the end, because we cannot make any more groups of 6 from just 3.

Therefore, 147 ÷ 6 = 24 r 3

This method shows 10 x 6 twice. If your student shows a good understanding of the concept, they might be able to see that 20 x 6 could have been used initially instead.


1 x 6 = 6	10 x 6 = 60
2 x 6 = 12	20 x 6 = 120
3 x 6 = 18	30 x 6 = 180
4 x 6 = 24	40 x 6 = 240

Watch Division with Chunking (YouTube) to understand how this can be used with even larger numbers too.

Once your student has remembered this method of division, look at the calculations on the page together and ask your student to copy and complete them on squared paper. Stay with your student to ensure they are doing them correctly.

Citations

[1] youtu.be [2] www.youtube.com