Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 947 · 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. 1.155 − 127 =
2. 2.936 − 799 =
3. 3.780 − 369 =
4. 4.773 − 298 =
5. 5.981 − 579 =
6. 6.898 − 699 =
7. 7.995 − 588 =
8. 8.730 − 188 =
9. 9.624 − 319 =
10. 10.796 − 697 =
11. 11.979 − 798 =
12. 12.964 − 799 =
13. 13.880 − 399 =
14. 14.851 − 499 =
15. 15.793 − 247 =
16. 16.937 − 498 =
17. 17.843 − 167 =
18. 18.872 − 398 =
19. 19.910 − 599 =
20. 20.433 − 299 =
21. 21.477 − 198 =
22. 22.247 − 197 =
23. 23.653 − 398 =
24. 24.932 − 677 =
25. 25.685 − 177 =
26. 26.728 − 298 =
27. 27.839 − 798 =
28. 28.774 − 599 =
29. 29.661 − 598 =
30. 30.941 − 798 =
31. 31.661 − 419 =
32. 32.588 − 298 =
33. 33.826 − 798 =
34. 34.764 − 687 =
35. 35.558 − 499 =
36. 36.832 − 419 =
37. 37.517 − 298 =
38. 38.647 − 599 =
39. 39.604 − 358 =
40. 40.748 − 699 =

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