Transcript Chunking - School Jotter

4
) 172
For this example, we will use the sum:
172 ÷ 4.
The first thing we do is write 172 at the top
of our page.
4
) 172
- 100
Next, think of an easy multiple of four. In
this example, we know that 4 lots of 25 is
100.
We can then subtract 100 from 172. This is
our first ‘chunk’.
4
) 172
- 100
(x25)
Next to 100, jot down that this is 25 lots of
4 (so 4 x 25). Then draw a line underneath.
4
) 172
- 100
(x25)
It is the same as saying:
“We can take a manageable chunk of our
total to work with. If we take 100 of our
total of 172, we know that there are 25 lots
of 4 in 100.”
4
) 172
- 100
72
(x25)
Next, we subtract 100 from 172, leaving us
with 72. We carry this out as a subtraction
calculation.
4
) 172
- 100
72
- 40
(x25)
We can now think of another easy multiple of
4 which is close to, but lower than 72. In this
case, we know 40 is
4 x 10. We write it underneath 72. This is our
second ‘chunk’.
4
) 172
- 100
72
- 40
(x25)
(x10)
Again, we know that 40 is 10 lots of 4 (4 x
10) and so we make a note of that in our
calculation.
4
) 172
- 100
72
- 40
32
(x25)
(x10)
As we did before, we now subtract 40 from
our remaining total (72 – 40).
4
) 172
- 100
72
- 40
32
- 32
(x25)
(x10)
(x8)
Now, we use our multiplication tables to
divide 32 by 4. We know that
8 x 4 = 32.
4
) 172
- 100
72
- 40
32
- 32
0
(x25)
(x10)
(x8)
Since 4 x 8 = 32, there won’t be a remainder.
4
)
172
- 100
72
- 40
32
- 32
0
(x25)
(x10)
(x8)
The final step is to add the numbers down the
right hand side of our calculation.
4
) 172
- 100
72
- 40
32
- 32
0
(x25)
(x10)
(x8)
2 5
+1 0
+ 8
4 3
When we add 25, 10 and 8 together,
we get a total of 43.
4
) 172
- 100
72
- 40
32
- 32
0
(x25)
(x10)
(x8)
This is our answer.
172 ÷ 4 = 43
2 5
+1 0
+ 8
4 3