2. Today we will be learning: that you can add in any order that subtraction is the inverse of addition.

3. Inverse means opposite. What does “inverse” mean?

4. Mental Activity We are going to practise adding numbers quickly. Add each pair of numbers as quickly as you can, then add 10 to the total.

5. 100 + 200310+ 10 =

6. 300 + 400710+ 10 =

7. 600 + 200810+ 10 =

8. 300 + 300610+ 10 =

9. 100 + 400510+ 10 =

10. 10 was added to a number and the answer was 56. What was the number? 46 20 was subtracted from a number and the answer was 37. What was the number? 57

11. 50 was added to a number and the answer was 72. What was the number? 22 100 was added to a number and the answer was 213. What was the number? 113

12. 200 was subtracted from a number and the answer was 423. What was the number? 623 300 was added to a number and the answer was 728. What was the number? 428

13. Main Activity Today we are going to work with addition and subtraction.

14. 4 + 5 = 9 Can you use these three numbers to make another addition sentence? 5 + 4 = 9 There are still 9 cubes in total.

15. 9 – 5 = 4 Can you use the three numbers 9 5 4 to make two different subtraction sentences? 9 – 4 = 5

16. 9 – 5 = 4 5 + 4 = 9 4 + 5 = 9 9 – 4 = 5 Can you see a pattern?

17. Top Tip Subtraction is the inverse of addition. Subtraction “undoes” addition.

18. Group Work Complete subtraction sentences by replacing the symbols with missing numbers. Use number lines to work out unknown numbers. Use inverse operations to find missing numbers.