Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 703 · 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. 1.944 − 497 =
2. 2.664 − 497 =
3. 3.219 − 199 =
4. 4.392 − 298 =
5. 5.405 − 297 =
6. 6.978 − 399 =
7. 7.623 − 499 =
8. 8.514 − 499 =
9. 9.945 − 567 =
10. 10.608 − 279 =
11. 11.294 − 169 =
12. 12.862 − 328 =
13. 13.784 − 347 =
14. 14.958 − 499 =
15. 15.872 − 139 =
16. 16.987 − 678 =
17. 17.527 − 297 =
18. 18.977 − 697 =
19. 19.303 − 278 =
20. 20.781 − 537 =
21. 21.842 − 698 =
22. 22.613 − 497 =
23. 23.826 − 297 =
24. 24.959 − 699 =
25. 25.831 − 498 =
26. 26.652 − 249 =
27. 27.957 − 598 =
28. 28.616 − 299 =
29. 29.738 − 297 =
30. 30.273 − 188 =
31. 31.837 − 597 =
32. 32.913 − 797 =
33. 33.336 − 299 =
34. 34.689 − 568 =
35. 35.807 − 538 =
36. 36.917 − 599 =
37. 37.696 − 597 =
38. 38.996 − 799 =
39. 39.709 − 548 =
40. 40.818 − 297 =

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