Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 795 · 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. 1.783 − 397 =
2. 2.888 − 397 =
3. 3.704 − 349 =
4. 4.418 − 397 =
5. 5.874 − 397 =
6. 6.308 − 199 =
7. 7.606 − 558 =
8. 8.759 − 479 =
9. 9.641 − 609 =
10. 10.927 − 797 =
11. 11.912 − 489 =
12. 12.807 − 697 =
13. 13.224 − 139 =
14. 14.970 − 798 =
15. 15.805 − 617 =
16. 16.854 − 299 =
17. 17.872 − 199 =
18. 18.985 − 797 =
19. 19.912 − 597 =
20. 20.981 − 619 =
21. 21.539 − 398 =
22. 22.424 − 177 =
23. 23.884 − 499 =
24. 24.876 − 468 =
25. 25.799 − 607 =
26. 26.757 − 499 =
27. 27.801 − 197 =
28. 28.889 − 369 =
29. 29.924 − 699 =
30. 30.609 − 198 =
31. 31.818 − 389 =
32. 32.626 − 499 =
33. 33.732 − 657 =
34. 34.563 − 498 =
35. 35.495 − 257 =
36. 36.664 − 599 =
37. 37.758 − 699 =
38. 38.738 − 297 =
39. 39.250 − 157 =
40. 40.558 − 399 =

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