Use and record a range of mental strategies to solve addition and subtraction problems involving two-digit numbers, including:the jump strategy on an empty number line, the split strategy, eg record how the answer to 37 + 45 was obtained using the split s

1. Which number is 10 less than 16?
2. Changing Numbers: 48 to 47
3. Changing Numbers: 27 to 29
4. Changing Numbers: 68 to 58
5. Changing Numbers: 90 to 85
6. Changing Numbers: 66 to 76
7. Number Detectives: 10 + 27 = ?
8. Same or Different: Click all the boxes with the answer 25.
9. Same or Different: Click all the boxes with the answer 37.
10. Same or Different: Click all the boxes with the answer 34.
11. Same or Different: Click all the boxes with the answer 26.
12. The 20s zone: 22-2=?, 22-5=?
13. The 20s zone: 21-1=?, 21-7=?
14. The 20s zone: 23-3=?, 23-8=?
15. The 20s zone: 25-5=?, 25-8=?
16. The 20s zone: 26-6=?, 26-9=?
17. The 20s zone: 23-3=?, 20-6=?
18. The 20s zone: 24-4=?, 24-6=?
19. The 20s zone: 22-2=?, 22-8=?
20. The 20s zone: 23-3=?, 23-6=?
21. The 20s zone: 27-7=?, 27-9=?
22. Beyond 30 - 7 more than 39
23. Beyond 30 - 8 more than 35
24. Beyond 30 - 7 more than 37
25. Beyond 30 - 6 more than 38