Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 22 · 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. 1.704 − 399 =
2. 2.902 − 189 =
3. 3.519 − 197 =
4. 4.826 − 437 =
5. 5.854 − 617 =
6. 6.387 − 128 =
7. 7.654 − 357 =
8. 8.662 − 638 =
9. 9.995 − 409 =
10. 10.956 − 798 =
11. 11.972 − 498 =
12. 12.785 − 699 =
13. 13.742 − 619 =
14. 14.764 − 299 =
15. 15.398 − 147 =
16. 16.963 − 699 =
17. 17.757 − 678 =
18. 18.773 − 259 =
19. 19.793 − 699 =
20. 20.768 − 649 =
21. 21.593 − 117 =
22. 22.972 − 399 =
23. 23.814 − 199 =
24. 24.542 − 377 =
25. 25.532 − 498 =
26. 26.552 − 199 =
27. 27.623 − 268 =
28. 28.620 − 598 =
29. 29.517 − 187 =
30. 30.816 − 498 =
31. 31.992 − 797 =
32. 32.693 − 198 =
33. 33.860 − 699 =
34. 34.822 − 797 =
35. 35.585 − 299 =
36. 36.929 − 167 =
37. 37.867 − 299 =
38. 38.409 − 249 =
39. 39.727 − 668 =
40. 40.963 − 519 =

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