Chunking
Chunking is an informal method of division which is based on our mental process when we divide in our head. This is the method now taught in schools.
On a number line
87÷7=
Subtract seven 12 times
There are 3 left over
So…..
87÷7=12 r 3
Vertically
372 ÷12
We use repeated multiplication with numbers that we are confident with such as 10 and 5. We know that 10 x 12 = 120 and 20 x 12 = 240 so we will start by deducting 240 from 372.
-240 (20x12)
-----
132
We now have 132 left over. We know that 10 x 12 = 120 so we will now deduct that.
-120 (10x12)
-----
12
We now have 12 left over. We know that 1 x 12 = 12. So we do the final step.
- 12 (1x12)
-----
0
31 x12 = 372 if there was a number left over that would be the remainder.
so you would write the answer 31 at the top.
Basically, you subtract multiples of the dividing number in large chunks until to can't go any further. You add the multiples together and there is your answer.
Here is a further example
674÷3=
674
-300 100 x3 (100 groups of 3)
374
-300 100x3 (100 groups of 3)
74
-60 20 x3 (20 groups of 3)
14
-12 4 x 3 (4 groups of 3)
2 224 x 3 (224 groups of 3)
And a remainder of 2