Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 782 · 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. 1.484 − 329 =
2. 2.471 − 298 =
3. 3.628 − 488 =
4. 4.518 − 429 =
5. 5.731 − 229 =
6. 6.608 − 397 =
7. 7.509 − 298 =
8. 8.731 − 199 =
9. 9.975 − 797 =
10. 10.953 − 797 =
11. 11.757 − 668 =
12. 12.660 − 597 =
13. 13.759 − 689 =
14. 14.722 − 528 =
15. 15.599 − 329 =
16. 16.943 − 799 =
17. 17.608 − 499 =
18. 18.536 − 497 =
19. 19.775 − 197 =
20. 20.608 − 197 =
21. 21.750 − 599 =
22. 22.601 − 387 =
23. 23.818 − 598 =
24. 24.618 − 297 =
25. 25.719 − 599 =
26. 26.821 − 588 =
27. 27.607 − 537 =
28. 28.983 − 599 =
29. 29.681 − 299 =
30. 30.752 − 478 =
31. 31.915 − 798 =
32. 32.662 − 647 =
33. 33.983 − 399 =
34. 34.592 − 409 =
35. 35.836 − 698 =
36. 36.806 − 498 =
37. 37.984 − 598 =
38. 38.865 − 799 =
39. 39.777 − 597 =
40. 40.825 − 799 =

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