Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 54 · 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. 1.960 − 299 =
2. 2.916 − 658 =
3. 3.736 − 187 =
4. 4.682 − 598 =
5. 5.154 − 127 =
6. 6.767 − 139 =
7. 7.810 − 299 =
8. 8.702 − 387 =
9. 9.987 − 698 =
10. 10.896 − 698 =
11. 11.241 − 198 =
12. 12.551 − 469 =
13. 13.710 − 599 =
14. 14.766 − 697 =
15. 15.635 − 148 =
16. 16.888 − 798 =
17. 17.907 − 619 =
18. 18.742 − 679 =
19. 19.692 − 497 =
20. 20.920 − 798 =
21. 21.711 − 299 =
22. 22.689 − 599 =
23. 23.629 − 497 =
24. 24.851 − 599 =
25. 25.884 − 629 =
26. 26.528 − 438 =
27. 27.946 − 127 =
28. 28.963 − 799 =
29. 29.993 − 648 =
30. 30.299 − 237 =
31. 31.669 − 597 =
32. 32.251 − 199 =
33. 33.413 − 399 =
34. 34.616 − 599 =
35. 35.732 − 398 =
36. 36.925 − 527 =
37. 37.680 − 409 =
38. 38.936 − 298 =
39. 39.988 − 299 =
40. 40.731 − 537 =

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