Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 763 · 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. 1.776 − 299 =
2. 2.530 − 137 =
3. 3.711 − 689 =
4. 4.592 − 299 =
5. 5.891 − 197 =
6. 6.831 − 299 =
7. 7.343 − 298 =
8. 8.583 − 399 =
9. 9.984 − 799 =
10. 10.849 − 517 =
11. 11.909 − 207 =
12. 12.645 − 409 =
13. 13.932 − 797 =
14. 14.768 − 539 =
15. 15.725 − 457 =
16. 16.900 − 689 =
17. 17.956 − 259 =
18. 18.814 − 287 =
19. 19.865 − 499 =
20. 20.933 − 797 =
21. 21.730 − 379 =
22. 22.677 − 177 =
23. 23.730 − 498 =
24. 24.372 − 149 =
25. 25.699 − 678 =
26. 26.493 − 237 =
27. 27.928 − 699 =
28. 28.807 − 547 =
29. 29.961 − 397 =
30. 30.288 − 179 =
31. 31.884 − 609 =
32. 32.855 − 799 =
33. 33.696 − 598 =
34. 34.957 − 409 =
35. 35.503 − 417 =
36. 36.556 − 368 =
37. 37.528 − 508 =
38. 38.445 − 398 =
39. 39.829 − 798 =
40. 40.755 − 598 =

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