Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 472 · 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. 1.756 − 197 =
2. 2.654 − 338 =
3. 3.623 − 597 =
4. 4.738 − 698 =
5. 5.770 − 498 =
6. 6.655 − 247 =
7. 7.570 − 539 =
8. 8.533 − 219 =
9. 9.955 − 598 =
10. 10.862 − 518 =
11. 11.859 − 699 =
12. 12.987 − 397 =
13. 13.817 − 798 =
14. 14.382 − 229 =
15. 15.659 − 617 =
16. 16.857 − 799 =
17. 17.669 − 197 =
18. 18.631 − 499 =
19. 19.599 − 557 =
20. 20.259 − 199 =
21. 21.704 − 597 =
22. 22.953 − 467 =
23. 23.849 − 579 =
24. 24.546 − 198 =
25. 25.862 − 539 =
26. 26.167 − 139 =
27. 27.965 − 529 =
28. 28.606 − 587 =
29. 29.749 − 697 =
30. 30.681 − 398 =
31. 31.894 − 397 =
32. 32.850 − 448 =
33. 33.943 − 179 =
34. 34.273 − 239 =
35. 35.803 − 159 =
36. 36.781 − 397 =
37. 37.493 − 397 =
38. 38.648 − 498 =
39. 39.517 − 497 =
40. 40.407 − 297 =

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