Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 860 · 40 questions

How to do it in your head (Round up, add back): Round the number you take away up to the next ten or hundred: 297 → 300 (3 too many). Take away the round number. Add back the extra, because you took away too much.

1. 1.716 − 697 =
2. 2.895 − 699 =
3. 3.900 − 598 =
4. 4.686 − 247 =
5. 5.577 − 518 =
6. 6.715 − 399 =
7. 7.883 − 299 =
8. 8.910 − 498 =
9. 9.573 − 499 =
10. 10.945 − 198 =
11. 11.929 − 609 =
12. 12.591 − 199 =
13. 13.740 − 198 =
14. 14.485 − 298 =
15. 15.745 − 227 =
16. 16.610 − 398 =
17. 17.986 − 438 =
18. 18.654 − 597 =
19. 19.627 − 499 =
20. 20.724 − 119 =
21. 21.557 − 499 =
22. 22.563 − 479 =
23. 23.920 − 279 =
24. 24.484 − 299 =
25. 25.994 − 299 =
26. 26.832 − 498 =
27. 27.292 − 168 =
28. 28.650 − 578 =
29. 29.722 − 297 =
30. 30.777 − 117 =
31. 31.599 − 199 =
32. 32.638 − 157 =
33. 33.831 − 168 =
34. 34.266 − 148 =
35. 35.915 − 699 =
36. 36.986 − 797 =
37. 37.832 − 599 =
38. 38.990 − 299 =
39. 39.662 − 339 =
40. 40.701 − 499 =

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