Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 786 · 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. 1.928 − 699 =
2. 2.969 − 298 =
3. 3.788 − 647 =
4. 4.503 − 268 =
5. 5.798 − 699 =
6. 6.853 − 797 =
7. 7.982 − 289 =
8. 8.787 − 397 =
9. 9.565 − 508 =
10. 10.681 − 499 =
11. 11.745 − 499 =
12. 12.805 − 409 =
13. 13.416 − 168 =
14. 14.427 − 297 =
15. 15.958 − 797 =
16. 16.849 − 639 =
17. 17.688 − 157 =
18. 18.551 − 207 =
19. 19.927 − 228 =
20. 20.692 − 527 =
21. 21.925 − 299 =
22. 22.964 − 228 =
23. 23.829 − 499 =
24. 24.958 − 598 =
25. 25.494 − 268 =
26. 26.827 − 659 =
27. 27.598 − 199 =
28. 28.999 − 798 =
29. 29.919 − 407 =
30. 30.712 − 199 =
31. 31.628 − 558 =
32. 32.425 − 247 =
33. 33.824 − 558 =
34. 34.916 − 697 =
35. 35.987 − 489 =
36. 36.379 − 197 =
37. 37.466 − 268 =
38. 38.644 − 597 =
39. 39.965 − 547 =
40. 40.549 − 179 =

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