1. ADDITION AND SUBTRACTION KS2

2. The key to successful addition and subtraction is a solid understanding of place value and number bonds. Year 3 – fluent in bonds to 10 and 20, and use this to derive other facts over 100. PV to 1000. Year 4 – using known bonds to derive other facts, over 1000. PV to 10000 Year 5/6 - using known bonds to derive other facts, including decimals.

3. Vocabulary

4. ADDITION – Mental Strategies  Counting on 534 + 150 (by partitioning the second number and counting on; +100, +50)  Partitioning 456 + 362 (400+300=700, 50+60=110, 6+2=8)  Adjusting 1435 + 199 (by adding 200 and subtracting 1)  Using know number facts 6060 + 47 60+47= 107 so 6060+47=6107  Estimating 2467 + 1729 is approximately 2500 + 1500

5. ADDITION - Partitioning 34 + 53 = ? + + 34 + 50 + 3 = ? 84 + 3 = 87

6. ADDITION - Partitioning 134 + 253 = ? 134 + 200 + 50 +3 = ? 334 + 50 + 3 = ? 384 + 3 = 387

7. ADDITION – Moving towards column method using manipulatives. 247 + 125 =

8. ADDITION – Moving towards column method. 247 + 125 = H T U 200 + 40 + 7 + 100 + 20 + 5 300 + 60 + 12 = 372

9. ADDITION – Expanded column addition. 247 + 125 = H T U 247 + 125 12 units 60 tens 300 hundreds 372

10. ADDITION – Expanded column addition. 341 + 253 = H T U 341 + 253 units tens hundreds00 387

11. ADDITION – Expanded column addition. 407 + 498 = H T U 407 + 498 15 90 800 905 1

12. ADDITION – condensed column addition. 2634 + 4517 =

13. ADDITION – Condensed column addition. 384 + 498 = 584 + 498 1082 11

14. ADDITION – Expanded column addition. 2384 + 6498 = 2584 + 6498 9082 11 1

15. SUBTRACTION – Mental strategies  Counting back 564 – 150 (by partitioning the second number and counting back; -100, -50)  Counting up 607 – 288 (by counting up from 288, bridging the hundreds boundary; +12, + 300, +7)  Adjusting 1487 – 199 (by subtracting 200 and adding 1)  Using know number facts 7000-600 1000-600=400 so 7000-600=6400  Estimating 3062-2581 is approximately 3000-2500

16. SUBTRACTION – Number lines  343 – 170 = ?  72 – 36 = ?

17. SUBTRACTION – Moving towards expanded column method with no decomposition. 98 - 35 = ? T U

18. SUBTRACTION – Moving towards expanded column method with decomposition. 52 - 37 = ? T U 50 2 - 30 7 40 12 - 30 7 T U

19. SUBTRACTION – Moving towards expanded column method with decomposition.

20. SUBTRACTION – condensed column method with out decomposition. 879 - 465 414 3995 - 2462 1533

21. SUBTRACTION – condensed column method with decomposition. 36.25 - 14.60 21.65 5 1