Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 694 · 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. 1.769 − 678 =
2. 2.959 − 399 =
3. 3.898 − 599 =
4. 4.392 − 297 =
5. 5.459 − 299 =
6. 6.907 − 698 =
7. 7.553 − 197 =
8. 8.907 − 297 =
9. 9.817 − 799 =
10. 10.202 − 117 =
11. 11.690 − 287 =
12. 12.666 − 217 =
13. 13.657 − 377 =
14. 14.646 − 248 =
15. 15.887 − 297 =
16. 16.674 − 399 =
17. 17.352 − 317 =
18. 18.814 − 199 =
19. 19.812 − 799 =
20. 20.939 − 798 =
21. 21.853 − 589 =
22. 22.316 − 159 =
23. 23.575 − 409 =
24. 24.633 − 249 =
25. 25.322 − 149 =
26. 26.997 − 599 =
27. 27.802 − 399 =
28. 28.522 − 138 =
29. 29.860 − 797 =
30. 30.831 − 399 =
31. 31.542 − 497 =
32. 32.611 − 398 =
33. 33.601 − 249 =
34. 34.924 − 399 =
35. 35.422 − 179 =
36. 36.300 − 119 =
37. 37.746 − 597 =
38. 38.880 − 298 =
39. 39.553 − 499 =
40. 40.689 − 199 =

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