Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 236 · 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. 1.876 − 797 =
2. 2.441 − 199 =
3. 3.932 − 697 =
4. 4.618 − 497 =
5. 5.639 − 597 =
6. 6.499 − 299 =
7. 7.830 − 688 =
8. 8.596 − 139 =
9. 9.801 − 699 =
10. 10.846 − 399 =
11. 11.976 − 497 =
12. 12.839 − 598 =
13. 13.628 − 337 =
14. 14.509 − 298 =
15. 15.603 − 149 =
16. 16.706 − 499 =
17. 17.833 − 697 =
18. 18.513 − 197 =
19. 19.945 − 597 =
20. 20.754 − 589 =
21. 21.723 − 698 =
22. 22.751 − 328 =
23. 23.560 − 299 =
24. 24.725 − 599 =
25. 25.956 − 398 =
26. 26.656 − 599 =
27. 27.816 − 298 =
28. 28.944 − 497 =
29. 29.680 − 579 =
30. 30.600 − 497 =
31. 31.463 − 388 =
32. 32.903 − 798 =
33. 33.569 − 297 =
34. 34.983 − 299 =
35. 35.717 − 397 =
36. 36.385 − 199 =
37. 37.774 − 398 =
38. 38.500 − 409 =
39. 39.977 − 658 =
40. 40.535 − 298 =

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