1. Addition and Subtraction Number facts and inverse operations
Objectives
Day 1
Know number facts to 20; Relate addition and subtraction in the context of number facts.
Day 2
Know number facts to 20; Understand the concept of equality & use the = sign; Relate addition and subtraction in the context of number facts.
Before teaching, be aware that:
On Day 1 you will need a coat hanger and 12 pegs in 2 colours to model partitioning , children need whiteboards and pens; Load online game for the WT group activity for use / display on the IWB.
On Day 2 you will need a number balance (or see NRICH link for online version).
Save the whale game
Online number balance
Year 3

2. Addition and Subtraction Number facts and inverse operations
Starters
Day 1
Addition facts for numbers 6 to 10 (pre-requisite skills)
Day 2
Pairs to 10 (simmering skills)
Choose starters that suit your class by dragging and dropping the relevant slide or slides below to the start of the teaching for each day.
Year 3

3. Addition and Subtraction
Number facts and inverse operations
Starter
Addition facts for numbers 6 to 10
Pre-requisite skills – to use this starter, drag this slide to the start of Day 1
Show the bar models pictures for 6 (see resources). Point to a question mark, children show on their fingers the number which belongs on this bar. Repeat for each bar to 6, then 7, 8 and 9.
Year 3

4. Addition and Subtraction Number facts and inverse operations
Starter
Pairs to 10
Simmering skills – to use this starter, drag this slide to the start of Day 2
Write 10 = on the board. Ask children to write down as many different ways of completing that sentence as possible. For example: 10 = , 10 = 5 + 5,
10 =
Year 3

5. Addition and Subtraction Number facts and inverse operations
Objectives
Day 1
Know number facts to 20; Relate addition and subtraction in the context of number facts.
Year 3

6. Talk to your partner – how do you think this sequence will continue?
Day 1: Know number facts to 20; Relate addition and subtraction in the context of number facts.
Let’s use this coat-hanger and pegs to find all the pairs of numbers with a total of 11.
11 =
11 =
11 = 9 + ?
Talk to your partner – how do you think this sequence will continue?
On your whiteboards write some number sentences to show ways to partition 11 pegs.
So, we know that…
11 = 9 + 2
11 = 2 + ?
So, what subtractions can we write…?
11 – 2 = ?
11 – 9 = ?
Year 3

7. This picture shows that 8 and 4 cubes is the same amount as 12 cubes.
Day 1: Know number facts to 20; Relate addition and subtraction in the context of number facts.
This picture shows that 8 and 4 cubes is the same amount as 12 cubes.
Write a number sentence to show this.
12 = 4 + 8
12 = 8 + 4
12 – 4 = 8
12 – 8 = 4
What are the four number sentences we can write for this 1 picture?
Year 3

8. We can also draw ‘bars’ to represent the cubes…
Day 1: Know number facts to 20; Relate addition and subtraction in the context of number facts.
We can also draw ‘bars’ to represent the cubes…
Year 3

9. Did each set of numbers have 4 addition and subtraction facts?
Day 1: Know number facts to 20; Relate addition and subtraction in the context of number facts.
In pairs, choose one of the number bars and write all of the addition and subtraction facts for it.
Today would be a great day to use a problem-solving investigation – Are You Well Balanced? from NRICH – as the group activity, which you can find in this unit’s IN-DEPTH INVESTIGATION box on our website.
Alternatively, 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: Online game to consolidate number bonds for numbers 6 – 9
ARE: Partition numbers into single digit pairs, sketching bar models and writing number sentences.
GD: Find all possibilities for making numbers 11-20, using two numbers.
Did each set of numbers have 4 addition and subtraction facts?
Year 3

10. Day 1: Know number facts to 20; Relate addition and subtraction in the context of number facts.
The Practice Sheet on this slide is suitable for most children.
Differentiated PRACTICE WORKSHEETS are available on Hamilton’s website in this unit’s PROCEDURAL FLUENCY box.
WT: Find missing numbers in bar models and addition sentences.
ARE: Find missing numbers in addition and subtraction sentences, sheet 3.
GD: Find missing numbers in addition and subtraction sentences, sheet 4.
Challenge
Year 3

11. Addition and Subtraction Number facts and inverse operations
Objectives
Day 2
Know number facts to 20; Understand the concept of equality & use the = sign; Relate addition and subtraction in the context of number facts.
Year 3

12. What should I put on the right to make it balance?
Day 2: Know number facts to 20; Understand the concept of equality and use the = sign; Relate addition and subtraction in the context of number facts.
Let’s put 6 and 4 on the left of the balance and 7 on the right. What will happen?
What should I put on the right to make it balance?
6 + 4
7 + ?
6 + 4 = 7 + ?
6 + 4 = 7 + 3
10 = 10
Year 3

13. What should I put on the left to make it balance?
Day 2: Know number facts to 20; Understand the concept of equality and use the = sign; Relate addition and subtraction in the context of number facts.
What should I put on the left to make it balance?
Now let’s put 6 on the left of the balance and 9 and 1 on the right. What will happen?
6 + ? = 9 + 1
Year 3

14. What should I put on the right to make it balance?
Day 2: Know number facts to 20; Understand the concept of equality and use the = sign; Relate addition and subtraction in the context of number facts.
Now let’s put 7 and 6 on the left of the balance and 8 on the right. What will happen?
What should I put on the right to make it balance?
7 + 6 = 8 + ?
Year 3

15. Day 2: Know number facts to 20; Understand the concept of equality and use the = sign; Relate addition and subtraction in the context of number facts.
Now let’s put 6 on the left of the balance and 9 and 4 on the right. What will happen?
Talk to your partner – what other pairs make 13? We can try them on the balance!
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: ‘What’s in the box’ game using a set of between 6 and 9 items
ARE: ‘What’s in the box’ game using a set of between 13 and 18 items
GD: ‘What’s in the box’ game using a set of 20 items
6 + ? = 9 + 4
Year 3

16. Day 2: Know number facts to 20; Understand the concept of equality and use the = sign; Relate addition and subtraction in the context of number facts.
The Practice Sheet on this slide is suitable for most children.
Differentiated PRACTICE WORKSHEETS are available on Hamilton’s website in this unit’s PROCEDURAL FLUENCY box.
WT: Balancing scales
ARE: Making 14 and 15
GD: Making 16, 17, 18, 19 and 20
Challenge
Year 3

17. Addition and Subtraction Number facts and inverse operations
Well Done! You’ve completed this unit.
Objectives
Day 1
Know number facts to 20; Relate addition and subtraction in the context of number facts.
Day 2
Know number facts to 20; Understand the concept of equality & use the = sign; Relate addition and subtraction in the context of 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 slide.
Year 3

18. Addition and Subtraction Unit 1
Problem solving and reasoning questions
Write four 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 similar addition with an answer of 200.
Repeat this.
Write three different ways of making 14 by adding two 1-digit numbers.
Year 3