Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 103 · 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. 1.471 − 297 =
2. 2.875 − 557 =
3. 3.987 − 298 =
4. 4.671 − 609 =
5. 5.638 − 517 =
6. 6.530 − 207 =
7. 7.281 − 198 =
8. 8.719 − 408 =
9. 9.712 − 497 =
10. 10.780 − 398 =
11. 11.747 − 298 =
12. 12.989 − 558 =
13. 13.619 − 598 =
14. 14.468 − 157 =
15. 15.941 − 798 =
16. 16.876 − 599 =
17. 17.985 − 199 =
18. 18.792 − 389 =
19. 19.775 − 647 =
20. 20.935 − 509 =
21. 21.552 − 459 =
22. 22.963 − 429 =
23. 23.420 − 269 =
24. 24.451 − 349 =
25. 25.874 − 798 =
26. 26.622 − 197 =
27. 27.929 − 697 =
28. 28.703 − 439 =
29. 29.742 − 488 =
30. 30.981 − 397 =
31. 31.351 − 137 =
32. 32.412 − 299 =
33. 33.529 − 479 =
34. 34.758 − 657 =
35. 35.961 − 598 =
36. 36.831 − 197 =
37. 37.889 − 457 =
38. 38.682 − 359 =
39. 39.639 − 497 =
40. 40.826 − 499 =

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