Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 170 · 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. 1.266 − 228 =
2. 2.596 − 437 =
3. 3.757 − 298 =
4. 4.675 − 418 =
5. 5.710 − 497 =
6. 6.735 − 439 =
7. 7.387 − 198 =
8. 8.923 − 799 =
9. 9.944 − 299 =
10. 10.345 − 299 =
11. 11.420 − 299 =
12. 12.715 − 198 =
13. 13.931 − 648 =
14. 14.331 − 197 =
15. 15.792 − 698 =
16. 16.674 − 539 =
17. 17.655 − 418 =
18. 18.849 − 698 =
19. 19.433 − 297 =
20. 20.674 − 498 =
21. 21.886 − 799 =
22. 22.508 − 399 =
23. 23.219 − 199 =
24. 24.915 − 797 =
25. 25.780 − 599 =
26. 26.861 − 287 =
27. 27.580 − 537 =
28. 28.683 − 599 =
29. 29.910 − 609 =
30. 30.823 − 798 =
31. 31.718 − 567 =
32. 32.790 − 119 =
33. 33.927 − 699 =
34. 34.420 − 139 =
35. 35.915 − 597 =
36. 36.827 − 259 =
37. 37.886 − 468 =
38. 38.741 − 689 =
39. 39.741 − 699 =
40. 40.696 − 598 =

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