Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 163 · 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. 1.987 − 467 =
2. 2.895 − 147 =
3. 3.633 − 619 =
4. 4.511 − 299 =
5. 5.525 − 499 =
6. 6.551 − 368 =
7. 7.442 − 207 =
8. 8.934 − 679 =
9. 9.814 − 799 =
10. 10.742 − 298 =
11. 11.626 − 599 =
12. 12.806 − 498 =
13. 13.712 − 198 =
14. 14.692 − 238 =
15. 15.888 − 599 =
16. 16.931 − 118 =
17. 17.944 − 598 =
18. 18.878 − 319 =
19. 19.339 − 249 =
20. 20.714 − 678 =
21. 21.670 − 298 =
22. 22.700 − 499 =
23. 23.607 − 299 =
24. 24.313 − 278 =
25. 25.896 − 697 =
26. 26.512 − 408 =
27. 27.550 − 199 =
28. 28.330 − 299 =
29. 29.880 − 497 =
30. 30.997 − 798 =
31. 31.836 − 799 =
32. 32.730 − 199 =
33. 33.799 − 397 =
34. 34.944 − 608 =
35. 35.265 − 217 =
36. 36.890 − 699 =
37. 37.413 − 299 =
38. 38.832 − 409 =
39. 39.632 − 498 =
40. 40.755 − 598 =

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