Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 878 · 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. 1.720 − 249 =
2. 2.782 − 699 =
3. 3.632 − 497 =
4. 4.219 − 127 =
5. 5.956 − 498 =
6. 6.808 − 529 =
7. 7.665 − 597 =
8. 8.501 − 248 =
9. 9.537 − 388 =
10. 10.995 − 197 =
11. 11.986 − 697 =
12. 12.779 − 128 =
13. 13.666 − 199 =
14. 14.706 − 498 =
15. 15.878 − 697 =
16. 16.946 − 497 =
17. 17.511 − 399 =
18. 18.550 − 359 =
19. 19.960 − 687 =
20. 20.758 − 307 =
21. 21.547 − 279 =
22. 22.836 − 699 =
23. 23.870 − 799 =
24. 24.506 − 488 =
25. 25.802 − 649 =
26. 26.504 − 197 =
27. 27.927 − 698 =
28. 28.976 − 299 =
29. 29.925 − 599 =
30. 30.670 − 499 =
31. 31.668 − 169 =
32. 32.944 − 499 =
33. 33.621 − 397 =
34. 34.814 − 587 =
35. 35.867 − 498 =
36. 36.815 − 197 =
37. 37.679 − 598 =
38. 38.718 − 297 =
39. 39.448 − 298 =
40. 40.823 − 517 =

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