Newdale Primary school
Maths Calculation Policy - Subtraction
Reception
Know that the number gets
smaller because objects have
been removed from the set.
Practical models of
subtraction
Counting back on fingers,
orally, number lines.
Year 1
Record subtraction by showing
jumps along number lines. Check
their answer using addition/inverse.
Subtracting bridging over 10
15 – 8 =7
Year 3
Partitioning on a numberline
HTU – TU, HTU – HTU
Partitioning on a numberline
Count back from the larger number in partitioned steps of
the smaller number to reach the unknown.
55 – 27 = 28
Partitioning on a numberline (larger numbers)
Using number bonds for subtraction
Know that numbers can be split to help solve a calculation so;
8 can be thought of as 5 and 3.
There were 9 balloons. Two
popped. How many are left?
Progress to bigger numbers
9–2=7
Find the difference where
numbers are close together.
“How many more do I add to 7 to
get to 9?”
783 - 356 =
Partitioning the 27 into 20, 5 and 2.
Find the difference, counting
on.
Practical demonstrations of
take away.
Year 2
Partitioning on a numberline TU –
TU
Find the difference by counting on
Know they can also find the difference by counting on along
a number line, begin to make decisions about which method
is the most appropriate.
15 – 8 =
+1 +1 + 1 +1 +1 +1 +1
__________________________________
8 9 10 11 12 13 14 15
Expanded decomposition method
89 = 80 and 9
- 24 = 20 and 4
65
60 and 5
“9 subtract 4 equals 5 and 80 subtract 20 equals 60.
60 and 5 make 65”
Newdale Primary school
Maths Calculation Policy - Subtraction
Year 4
Consolidate using expanded
decomposition methods to include:
ThHTU – HTU ThHTU – ThHTU and
decimals (2dp)
Expanded decomposition – carrying
81 = 80
1
- 57
50
7
__
_________= 24
81 = 70
11
- 57
50
7
__
_________= 24
“1 to subtract 7 is tricky so I will rearrange 81 into 70 and 11.
11 subtract 7 equals 4 and 70 subtract 50 equals 20. 20 and
4 make 24.”
Expanded Decomposition with decimals
£
8.95
.
-4 38
8.95
-4.38
£
8 . 90
.
4 30
4 . 50
5
8
7 = 4.57
£
80
.
30
.
50
15
8
7 = 4.57
£
7
4
4
.
Year 5
Compact Decomposition
Key Skill: Children are taught to cross out the numbers and replace
them with the exchanged number.
Year 6
Add with increasingly large numbers using the compact method.
Extend methods to include decimals to two decimal places.