Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 854 · 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. 1.919 − 797 =
2. 2.720 − 629 =
3. 3.531 − 398 =
4. 4.997 − 697 =
5. 5.535 − 498 =
6. 6.873 − 447 =
7. 7.764 − 497 =
8. 8.916 − 699 =
9. 9.889 − 118 =
10. 10.691 − 549 =
11. 11.882 − 479 =
12. 12.780 − 609 =
13. 13.278 − 199 =
14. 14.943 − 477 =
15. 15.601 − 489 =
16. 16.761 − 499 =
17. 17.807 − 478 =
18. 18.329 − 208 =
19. 19.879 − 228 =
20. 20.675 − 349 =
21. 21.755 − 497 =
22. 22.756 − 597 =
23. 23.924 − 647 =
24. 24.860 − 599 =
25. 25.566 − 167 =
26. 26.459 − 199 =
27. 27.959 − 228 =
28. 28.658 − 619 =
29. 29.475 − 318 =
30. 30.837 − 798 =
31. 31.733 − 497 =
32. 32.277 − 197 =
33. 33.789 − 699 =
34. 34.916 − 499 =
35. 35.645 − 198 =
36. 36.625 − 117 =
37. 37.309 − 248 =
38. 38.528 − 298 =
39. 39.712 − 397 =
40. 40.875 − 497 =

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