Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 716 · 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. 1.983 − 399 =
2. 2.996 − 489 =
3. 3.615 − 199 =
4. 4.931 − 799 =
5. 5.650 − 227 =
6. 6.813 − 218 =
7. 7.713 − 298 =
8. 8.580 − 427 =
9. 9.605 − 188 =
10. 10.989 − 799 =
11. 11.737 − 197 =
12. 12.856 − 637 =
13. 13.881 − 698 =
14. 14.590 − 439 =
15. 15.872 − 697 =
16. 16.684 − 539 =
17. 17.920 − 597 =
18. 18.931 − 199 =
19. 19.474 − 199 =
20. 20.307 − 278 =
21. 21.598 − 199 =
22. 22.778 − 697 =
23. 23.902 − 799 =
24. 24.535 − 249 =
25. 25.634 − 399 =
26. 26.774 − 457 =
27. 27.249 − 119 =
28. 28.669 − 228 =
29. 29.692 − 659 =
30. 30.792 − 598 =
31. 31.133 − 119 =
32. 32.769 − 499 =
33. 33.845 − 397 =
34. 34.818 − 697 =
35. 35.928 − 499 =
36. 36.541 − 358 =
37. 37.866 − 407 =
38. 38.928 − 198 =
39. 39.896 − 619 =
40. 40.958 − 478 =

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