Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 685 · 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. 1.826 − 199 =
2. 2.565 − 147 =
3. 3.438 − 127 =
4. 4.867 − 639 =
5. 5.842 − 698 =
6. 6.943 − 659 =
7. 7.528 − 259 =
8. 8.981 − 628 =
9. 9.739 − 299 =
10. 10.960 − 549 =
11. 11.838 − 399 =
12. 12.691 − 277 =
13. 13.773 − 199 =
14. 14.564 − 299 =
15. 15.459 − 378 =
16. 16.957 − 657 =
17. 17.820 − 549 =
18. 18.581 − 399 =
19. 19.956 − 417 =
20. 20.980 − 487 =
21. 21.856 − 668 =
22. 22.975 − 638 =
23. 23.471 − 398 =
24. 24.486 − 128 =
25. 25.898 − 198 =
26. 26.645 − 408 =
27. 27.823 − 328 =
28. 28.615 − 539 =
29. 29.872 − 689 =
30. 30.652 − 497 =
31. 31.431 − 299 =
32. 32.734 − 599 =
33. 33.558 − 197 =
34. 34.939 − 697 =
35. 35.630 − 338 =
36. 36.513 − 199 =
37. 37.866 − 569 =
38. 38.604 − 549 =
39. 39.790 − 137 =
40. 40.775 − 137 =

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