Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 987 · 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. 1.439 − 367 =
2. 2.802 − 698 =
3. 3.719 − 559 =
4. 4.929 − 198 =
5. 5.416 − 297 =
6. 6.739 − 497 =
7. 7.625 − 538 =
8. 8.687 − 428 =
9. 9.760 − 599 =
10. 10.911 − 497 =
11. 11.778 − 698 =
12. 12.186 − 159 =
13. 13.878 − 399 =
14. 14.271 − 198 =
15. 15.718 − 159 =
16. 16.794 − 597 =
17. 17.677 − 659 =
18. 18.995 − 639 =
19. 19.596 − 298 =
20. 20.640 − 598 =
21. 21.766 − 517 =
22. 22.796 − 597 =
23. 23.951 − 799 =
24. 24.750 − 598 =
25. 25.667 − 248 =
26. 26.856 − 799 =
27. 27.853 − 627 =
28. 28.989 − 797 =
29. 29.769 − 598 =
30. 30.876 − 499 =
31. 31.738 − 409 =
32. 32.978 − 798 =
33. 33.467 − 127 =
34. 34.262 − 209 =
35. 35.430 − 257 =
36. 36.817 − 459 =
37. 37.429 − 397 =
38. 38.783 − 699 =
39. 39.903 − 338 =
40. 40.650 − 198 =

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