Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 665 · 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. 1.639 − 278 =
2. 2.670 − 377 =
3. 3.826 − 367 =
4. 4.671 − 597 =
5. 5.822 − 297 =
6. 6.520 − 398 =
7. 7.949 − 118 =
8. 8.761 − 598 =
9. 9.692 − 498 =
10. 10.281 − 207 =
11. 11.871 − 569 =
12. 12.925 − 398 =
13. 13.817 − 597 =
14. 14.486 − 198 =
15. 15.730 − 659 =
16. 16.657 − 298 =
17. 17.931 − 389 =
18. 18.527 − 218 =
19. 19.704 − 598 =
20. 20.654 − 399 =
21. 21.978 − 698 =
22. 22.579 − 457 =
23. 23.756 − 698 =
24. 24.335 − 297 =
25. 25.584 − 568 =
26. 26.696 − 658 =
27. 27.921 − 697 =
28. 28.834 − 589 =
29. 29.930 − 298 =
30. 30.654 − 608 =
31. 31.632 − 227 =
32. 32.485 − 359 =
33. 33.606 − 199 =
34. 34.745 − 259 =
35. 35.646 − 177 =
36. 36.854 − 599 =
37. 37.365 − 298 =
38. 38.732 − 498 =
39. 39.725 − 199 =
40. 40.899 − 499 =

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