Dear Parents/Carers
This leaflet is designed to give you some practical advice to assist your child with
addition and subtraction strategies at home. You can click on links to short
videos which will illustrate some of the strategies.
The strategies are taught progressively throughout the school, with not all
children learning the same strategies at the same time.
Becoming more agile with mental calculation of numbers gives children a sound
base on which to build more complex mathematical learning and problem solving
skills.
You will notice that the more formal written algorithm (sum) is only
introduced once children are competent at mental calculations and usually
once 3 digits are beginning to be used.
At home, you can support your children in numeracy in a number of ways:
DO:
DO NOT:
Make numeracy as fun as possible.
Put your child under pressure.
Relate numbers to real life situations.
Be tempted to start formal written
Encourage children to have a go.
‘sums’ too soon.
Praise achievements however small.
Jump in too quickly with the answer –
Encourage children to tell you how they
encourage children to solve problems for
have worked something out.
Themselves.
Worry about mistakes – they are learning
opportunities.
Count forwards and backwards to/from 5,10,20 and beyond - Particularly focus on
crossing decades e.g. 12,11,10,9
28,29,30,31
Ask questions like ‘What comes before, after, between…’?
Count collections of items - Encourage children to put collections in a line to count
Count out requested number of items - e.g. give me four counters
Count items of two collections - e.g. How many altogether?
Count items in two rows - e.g. How many altogether?
(top line no bigger than 10)
https://
Counting items in two collections when first collection is hidden
www.yo
e.g. Here are 6 counters (then hide), here are 4 counters – How many altogether?
utube.co
Next, repeat hiding the 2nd collection
Counting items in two screened (hidden) collections
e.g.
Here are 3 counters and 4 counters (then hide both). How many altogether?
m/watch
?v=mtXZ
wbcSctQ
Missing number sums - e.g. Here are 7 counters. I have 10 counters altogether. How
many are under my second screen?
Missing number sums e.g. ‘I have 8 counters’ (then remove some counters without child
looking and hide them). ‘I had 8 counters now there are 5. How many did I remove?
Then
‘I took away 5 counters’. (Show then hide). ‘When I took them away I was left with 3
counters’. (Again these are shown and hidden). How many did I begin with?
The progression for these activities is to work within 5, then 10. Only once children
are confident doing these within 10 should they move on to doing the activities
within 20.
Next, children will begin to learn addition and subtraction facts within 20
using a variety of increasingly sophisticated methods such as:

Fingers

Cubes

Counters

Ten Frames
+
and
-
+ or + or -

Flash Cards

Blank Number Lines
9-4
4+5
12+6
18-7
e.g. 6+7
9-4
These facts will then be developed through a range of strategies

Doubles and near doubles
6+6=12 so 6+5=11 and 6+7=13
14-7=7 so 14-6=8 and 14-8=6

Partitioning numbers i.e. splitting numbers into tens and units, then add or
subtract tens and units. Finally put answers together
42 - 15
10
https://
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5
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
Rounding numbers
6 + 11
(6 + 10 = 16, then + 1)
18 – 6
(20 – 6 = 14, then + 2)

Reversing Sums
(Encourage children to see the link between sums).
7 + 6 = 13 so 6 + 7 = 13
20 – 5 = 15 so 20 – 15 = 5

Link addition and subtraction
7 + 8 = 15
so
15 – 8 = 7
Children will use ten frames, cubes and blank number lines to practise adding
and subtracting to and from decades e.g. 20 + 3 = 23
35 – 5 = 30
Then adding and subtracting through a decade – using blank number lines and
learning to move on from counting on or back in single steps
26 + 8 =
87 + 9 =
https://
www.yo
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m/watch
?v=GNQ
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g
OR
64 – 30 =
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47 - 23 =
OR
Children will develop and practise these strategies in word problems too.
They will then progress from using 2 digit numbers to 3 digit numbers
www.yo
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m/watch
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R08
265 – 186 =
326 + 294 =
When children are secure in these methods, algorithms (written methods) will
be taught.
Addition
Step 1
e.g.
738 + 46
738
+ 46
14 Add the units
70 Add the tens
700 Add the hundreds
784 Total
Step 2
e.g.
275 + 59
275
+ 59
Record units and carry the 10
4
https://
www.yo
utube.co
m/watch
?v=GXml
GAiIAE0
Add units
1
275
+ 59
Add the tens
Record the 30 and carry the 100
34
1 1
275
+ 59
334
1 1
Add the hundreds
Record the 300 for the final answer
Subtraction
Step 1
e.g.
368 – 42
300 + 60 + 8
First – partition the numbers
40 + 2
300 + 20 + 6 = 326
Next – subtract (8-2=6 60-40=20 300-0=300)
Then add subtractions
Step 2 (with exchanging)
e.g.
536-78
500 + 30 + 6
First – partition the numbers
70 + 8
Then, as 30-70 and 6-8 cannot be done, exchanging takes place
400 + 130 + 6
70 + 8
Exchange a hundred into the tens
Then, exchange a ten into the units
400 + 120 + 16
70 + 8
400 + 50 + 8 = 458
Step 3 (with exchanging)
3 1
243
-27
243
-27
3 1
243
-27
216
https://
www.yo
utube.co
m/watch
?v=0Cgw
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Children will then continue to develop these strategies, apply them to solve a
range of problems and use increasingly larger numbers. They will also learn
to use the most efficient method for the problem given.