1. Addition and Subtraction Strategies for addition and subtraction
Objectives
Day 1
Know number facts to 20; Understand the concept of equality and use the = sign; Relate addition and subtraction in the context of number facts.
Add pairs of 2-digit numbers using a mental strategy.
Day 2
Add 1-digit numbers to 2-digit numbers using number facts.
Add 1-digit numbers to 3-digit numbers using number facts.
Day 3
Subtract 1-digit numbers from 2-digit numbers using number facts.
Subtract 1-digit numbers from 3-digit numbers using number facts.
Before teaching, be aware that:
On Day children will need mini-whiteboards and pens.
Year 3/4

2. Addition and Subtraction Strategies for addition and subtraction
Short Mental Workouts
Day 1
Addition facts for numbers 6 to 10.
Day 2
Know by heart totals of any pair of 1-digit numbers.
Day 3
Complements to multiples of 10.
The short activities suggested here do not have to be done at the beginning of your maths lesson - they are suitable for doing at any time of the day to provide ongoing revision of important mental and oral skills.
While there probably isn’t time during your maths lesson for these activities, it is crucial to regularly revisit the skills used. If you decide to use them – perhaps at the beginning of the day for ‘morning maths’, as you line up for lunch, or as a ‘brain-break’ during the afternoon - it might be useful to drag and drop the relevant slide or slides below to that day’s teaching.
Year 3/4

3. Addition and Subtraction
Strategies for addition and subtraction
Short Mental Workout
Addition facts for numbers 6 to 10.
You can choose to drag this and the following slide to the start of Day 1
Show the bar model pictures for 6 (see next slide) Point to a question mark, showing a missing number. Children show the missing number on their fingers. Repeat for each bar to 6, then 7, 8 and 9.
Year 3/4

4. Year 3/4

5. Addition and Subtraction
Strategies for addition and subtraction
Short Mental Workout
Know by heart totals of any pair of 1-digit numbers.
You can choose to drag this slide to the start of Day 2
Model playing Flippy Floppy Fingers in pairs. Children shake their fingers saying ‘Flippy Floppy Fingers’. They show any number of fingers then try to find the total before their partner. First to say the total wins a cube. After 3 minutes, children put their cubes together. Which pairs won more than 20 cubes?
Year 3/4

6. Addition and Subtraction
Strategies for addition and subtraction
Short Mental Workout
Complements to multiples of 10.
You can choose to drag this slide to the start of Day 3
Show 37 on the 100 bead bar, children show digit card with the complement (3) to the next 10 (40). Repeat with other 2-digit numbers, first with the 100 bead bar and then without.
Year 3/4

7. Addition and Subtraction Strategies for addition and subtraction
Objectives
Day 1
Know number facts to 20; Understand the concept of equality and use the = sign; Relate addition and subtraction in the context of number facts.
Add pairs of 2-digit numbers using a mental strategy.
Year 3/4

8. This picture shows that 8 and 4 cubes are the same amount as 12 cubes.
Day 1: Know number facts to 20; Understand the concept of equality and use the = sign; Relate addition and subtraction in the context of number facts; Add pairs of 2-digit numbers using a mental strategy.
This picture shows that 8 and 4 cubes are the same amount as 12 cubes.
12 = and 12 = 8 + 4
= 8
If we took away 4 cubes how many would be left?
What if we took away 8 cubes instead?
= 4
Year 3/4

9. We can write 4 number sentences for this picture…
Day 1: Know number facts to 20; Understand the concept of equality and use the = sign; Relate addition and subtraction in the context of number facts; Add pairs of 2-digit numbers using a mental strategy.
8 + 4 = 12
4 + 8 = 12
= 8
= 4
We can write 4 number sentences for this picture…
We can also draw bars to represent the cubes…
Year 3/4

10. Did each set of numbers have 4 addition and subtraction facts?
Day 1: Know number facts to 20; Understand the concept of equality and use the = sign; Relate addition and subtraction in the context of number facts; Add pairs of 2-digit numbers using a mental strategy.
In pairs, choose one of the number bars and write all of the addition and subtraction facts for it.
Did each set of numbers have 4 addition and subtraction facts?
Are there any other pairs of numbers that add to 12?
Year 3/4

11. Day 1: Know number facts to 20; Understand the concept of equality and use the = sign; Relate addition and subtraction in the context of number facts; Add pairs of 2-digit numbers using a mental strategy.
What should I put on the right to make it balance?
Let’s put 6 and 4 on the left of the balance and 7 on the right. What will happen?
6 + 4
7 + 3
7 + ?
6 + 4 = 7 + 3
6 + 4 = 7 + ?
The equals sign acts like the middle of a see-saw…
Year 3/4

12. What should I put on the left to make it balance?
Day 1: Know number facts to 20; Understand the concept of equality and use the = sign; Relate addition and subtraction in the context of number facts; Add pairs of 2-digit numbers using a mental strategy.
What should I put on the left to make it balance?
Let’s put 6 on the left on the left of the balance and 9 and 1 on the right…
6 + 4
6 + ?
9 + 1
6 + 4 = 9 + 1
6 + ? = 9 + 1
Year 3/4

13. Day 1: Know number facts to 20; Understand the concept of equality and use the = sign; Relate addition and subtraction in the context of number facts; Add pairs of 2-digit numbers using a mental strategy.
What should I put on the right to make it balance?
Let’s put 7 and 6 on the left of the balance and 8 on the right…
7 + 6
8 + 5
8 + ?
7 + 6 = 8 + 5
7 + 6 = 8 + ?
Year 3/4

14. What should I put on the left to make it balance?
Day 1: Know number facts to 20; Understand the concept of equality and use the = sign; Relate addition and subtraction in the context of number facts; Add pairs of 2-digit numbers using a mental strategy.
What should I put on the left to make it balance?
Let’s put 6 on the left on the left of the balance and 9 and 4 on the right…
6 + 7
6 + ?
9 + 4
6 + 7 = 9 + 4
6 + ? = 9 + 4
Year 3/4

15. How can you be sure you have found them all?
Day 1: Know number facts to 20; Understand the concept of equality and use the = sign; Relate addition and subtraction in the context of number facts; Add pairs of 2-digit numbers using a mental strategy.
Talk to your partner – what other pairs make 13? We can try them on the balance!
How can you be sure you have found them all?
Y3 Children can now go on to do differentiated GROUP ACTIVITIES. You can find Hamilton’s group activities in this unit’s TEACHING AND GROUP ACTIVITIES download.
WT/ARE/GD: Explore and write equalities (‘balancing’ sums).
Year 3/4

16. The Practice Sheet on this slide is suitable for most Y3 children.
Differentiated PRACTICE WORKSHEETS are available on Hamilton’s website in this unit’s PROCEDURAL FLUENCY box.
WT: Balancing the scales Sheet 1.
ARE/GD: Making 14 and 15 Sheet 2.
Challenge
Year 3/4

17. Day 1: Add pairs of 2-digit numbers using a mental strategy.+ 48 80 24 57
Which is the best way to do each of these 4 additions? Choose a pair of numbers to add.
Further teaching for Year 4
Year 3/4

18. Day 1: Add pairs of 2-digit numbers using a mental strategy.
Here are some examples…
I can add 24 and 48 by partitioning and recombining…
= = = 72
I can add 80 and 24 by adding 20 to 80 and then 4 more.
I can add 48 to 57 by adding 50 then subtracting 2.
Y4 Children can now go on to do differentiated GROUP ACTIVITIES. You can find Hamilton’s group activities in this unit’s TEACHING AND GROUP ACTIVITIES download.
WT/ARE/GD: Investigate ways in which digits can be arranged in an addition grid to give ascending totals, totals <100 and totals >100.
Any other ideas?
Year 3/4

19. The Practice Sheet on this slide is suitable for most Y4 children.
Differentiated PRACTICE WORKSHEETS are available on Hamilton’s website in this unit’s PROCEDURAL FLUENCY box.
WT/ARE/GD: Adding 2-digit numbers Sheet 3.
Year 3/4

20. Addition and Subtraction Strategies for addition and subtraction
Objectives
Day 2
Add 1-digit numbers to 2-digit numbers using number facts.
Add 1-digit numbers to 3-digit numbers using number facts.
Year 3/4

21. Let’s use this bead bar to help us find 15 + 3.
Day 2: Add 1-digit numbers to 2-digit numbers using number facts; Add 1-digit numbers to 3-digit numbers using number facts. 15 25 35
Now let’s try and
Let’s use this bead bar to help us find
Y4s: What is
? ?
? ?
Y3s: How will this sequence continue?
Year 3/4

22. Day 2: Add 1-digit numbers to 2-digit numbers using number facts; Add 1-digit numbers to 3-digit numbers using number facts. 17
What do we need to add to 17 to make 20?
How much of the 7 is left to add on to 20?
What is ?
What if we want to add 7 to 27?
Year 3/4

23. Let’s try 37 + 7. We can draw the steps on the number line to help…
Day 2: Add 1-digit numbers to 2-digit numbers using number facts; Add 1-digit numbers to 3-digit numbers using number facts. 3 4 37 44
= 44
Let’s try We can draw the steps on the number line to help…
What would and be? What would the jumps look like?
Year 3/4

24. Y3: How can you work out 58 + 7? Would you
Day 2: Add 1-digit numbers to 2-digit numbers using number facts; Add 1-digit numbers to 3-digit numbers using number facts. 2 5
Y3: How can you work out ? Would you
split 7 the same way? 58 60 65
= 65
We can show that on an empty number line.
Y4: How can you work out ?
What is ?
Children can now go on to do differentiated GROUP ACTIVITIES. You can find Hamilton’s group activities in this unit’s TEACHING AND GROUP ACTIVITIES download.
Y3 WT: Play ‘Clue Cards - Identify mystery numbers by spotting the patterns of adding given 1-digit to 2-digit numbers.
Y3 ARE/GD: Play ‘Mystery Numbers - Identify mystery numbers by spotting the patterns of adding given 1-digit to 2-digit numbers.
Y4 WT/ARE/GD: Repeatedly add a 1-digit number to a 3-digit number; describe and explain any patterns in the ones digits.
Year 3/4

25. Challenge
The Practice Sheet on this slide is suitable for most Y3 children.
Differentiated PRACTICE WORKSHEETS are available on Hamilton’s website in this unit’s PROCEDURAL FLUENCY box.
WT/ARE/GD: Adding a 1-digit number to a 2- or 3-digit number Sheet 1.
Working towards ARE try questions 1 to 12 in each set with support.
Working at ARE complete questions 1 to 12 in each set.
Greater Depth complete questions 5 to 16 in each set.
Encourage children to use number facts rather than counting on each time.
Give children grids or 0 to 100 beaded lines if necessary (see resources).
Year 3/4

26. The Practice Sheet on this slide is suitable for most Y4 children.
Differentiated PRACTICE WORKSHEETS are available on Hamilton’s website in this unit’s PROCEDURAL FLUENCY box.
WT/ARE/GD: Adding a 1-digit to a 2- or 3-digit number Sheet 2.
Working towards ARE complete questions 1 to 5.
Working at ARE complete questions 1 to 5 and the Challenge.
Greater Depth complete question 3 to 7 and the Challenge
Challenge
Year 3/4

27. Addition and Subtraction Strategies for addition and subtraction
Objectives
Day 3
Subtract 1-digit numbers from 2-digit numbers using number facts.
Subtract 1-digit numbers from 3-digit numbers using number facts.
Year 3/4

28. Let’s use this bead bar to help us find 15 - 2.
Day 3: Subtract 1-digit numbers from 2-digit numbers using number facts; Subtract 1-digit numbers from 3-digit numbers using number facts. 25 35 15
So what is and ?
Let’s use this bead bar to help us find
What number fact helps?
Y3: Talk to your partner – how do you think this sequence will continue?
Y4: What is ? ? ?
Year 3/4

29. Day 3: Subtract 1-digit numbers from 2-digit numbers using number facts; Subtract 1-digit numbers from 3-digit numbers using number facts. 24
Knowing that we can split the 7 into 4 and 3 makes finding
24 -7 a quick, 2-step strategy:
is 20. That’s a place value subtraction.
Then = 17. That’s a number fact we know, based on =7.
What is ?
What is ?
How can we split the 7 to help?
Year 3/4

30. Let’s try 34 - 7. We can draw the steps on the number line to help…
Day 3: Subtract 1-digit numbers from 2-digit numbers using number facts; Subtract 1-digit numbers from 3-digit numbers using number facts. 3 4 27 34
= 27.
Let’s try We can draw the steps on the number line to help…
What would and be? What would the jumps look like?
Year 3/4

31. Y3: How can you work out 62 - 7? How would you split the 7?
Day 3: Subtract 1-digit numbers from 2-digit numbers using number facts; Subtract 1-digit numbers from 3-digit numbers using number facts.
Y3: How can you work out ? How would you split the 7? 5 2 55 60 62
= 55
We can show that on an empty number line.
Y4: How can you work out ?
What is ?
Children can now go on to do differentiated GROUP ACTIVITIES. You can find Hamilton’s group activities in this unit’s TEACHING AND GROUP ACTIVITIES download.
Y3 WT: Dice game subtracting from 2-digit numbers.
Y3 ARE/GD: Game using cards to make subtractions of 1-digit from 2-digit numbers.
Y4 WT/ARE/GD: Dice game subtracting from 3-digit numbers.
Year 3/4

32. The Practice Sheet on this slide is suitable for most Y3 children.
Differentiated PRACTICE WORKSHEETS are available on Hamilton’s website in this unit’s PROCEDURAL FLUENCY box.
WT/ARE/GD: Subtracting a 1-digit from a 2- or 3-digit number Sheet 1.
Working towards ARE try questions 1 to 12 in each set with support.
Working at ARE complete questions 1 to 12 in each set.
Greater Depth complete questions 5 to 16 in each set.
Encourage children to use number facts rather than counting back in ones. Give children 0 to 100 beaded lines if necessary (see resources).
Challenge
Year 3/4

33. Challenge
The Practice Sheet on this slide is suitable for most Y4 children.
Differentiated PRACTICE WORKSHEETS are available on Hamilton’s website in this unit’s PROCEDURAL FLUENCY box.
WT/ARE/GD: Subtracting a 1-digit number from a 2- or 3-digit number Sheet 2.
Working towards ARE complete questions 1 to 5.
Working at ARE complete questions 1 to 5 and the Challenge.
Greater Depth complete question 3 to 7 and the Challenge.
Year 3/4

34. Addition and Subtraction Strategies for addition and subtraction
Well Done! You’ve completed this unit.
Objectives
Day 1
Know number facts to 20; Understand the concept of equality and use the = sign; Relate addition and subtraction in the context of number facts.
Add pairs of 2-digit numbers using a mental strategy.
Day 2
Add 1-digit numbers to 2-digit numbers using number facts.
Add 1-digit numbers to 3-digit numbers using number facts.
Day 3
Subtract 1-digit numbers from 2-digit numbers using number facts.
Subtract 1-digit numbers from 3-digit numbers using number facts.
You can now use the Mastery: Reasoning and Problem-Solving questions to assess children’s success across this unit. Go to the next slides.
Year 3/4

35. Problem solving and reasoning questions
Year 3
Write 4 number sentences to relate these three numbers: 13, 19 and 6.
We know = 20. So, what is ?
We know = 20. So, what is ?
Write an addition with an answer of 20.
Write a related addition with an answer of 200.
Repeat for two more pairs of numbers that total 20, then 200.
Year 3/4

36. Problem solving and reasoning answers
Year 3
Write 4 number sentences to relate these three numbers: 13, 19 and 6.
= 19, = 19, = 6, = 13
We know = 20. So, what is ? 200
We know = 20. So, what is ? 200
Write an addition with an answer of 20. Write a related addition with an answer of 200.
Repeat for two more pairs of numbers that total 20, then 200.
e.g = 20, = 200
= 20, = 200.
Do children make the connection between the initial number fact to 20 and the subsequent questions?
Year 3/4

37. Problem solving and reasoning questions
Year 4
Write 4 number sentences to relate these three numbers: 240, 390 and 150.
Use a mental method to find:
200 – 52
73 – 25
630 – 150
Year 3/4

38. Problem solving and reasoning answers
Year 4
Write 4 number sentences to relate these three numbers: 240, 390 and 150.
= 390, = 390, = 240, = 150
Use a mental method to find: – –
630 –
Check children’s strategies- are they best suited for the numbers, for example adding and adjusting ( ), using complements ( ), bridging (73 – 25). Can they explain their choices?
Year 3/4