Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 196 · 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. 1.960 − 798 =
2. 2.954 − 199 =
3. 3.870 − 699 =
4. 4.811 − 498 =
5. 5.972 − 299 =
6. 6.837 − 498 =
7. 7.851 − 798 =
8. 8.938 − 799 =
9. 9.888 − 597 =
10. 10.608 − 569 =
11. 11.998 − 498 =
12. 12.579 − 499 =
13. 13.467 − 398 =
14. 14.300 − 118 =
15. 15.949 − 799 =
16. 16.603 − 367 =
17. 17.924 − 517 =
18. 18.773 − 659 =
19. 19.660 − 118 =
20. 20.910 − 598 =
21. 21.560 − 388 =
22. 22.735 − 368 =
23. 23.935 − 539 =
24. 24.648 − 619 =
25. 25.982 − 799 =
26. 26.412 − 199 =
27. 27.907 − 197 =
28. 28.844 − 338 =
29. 29.846 − 578 =
30. 30.390 − 297 =
31. 31.605 − 519 =
32. 32.731 − 688 =
33. 33.684 − 597 =
34. 34.832 − 699 =
35. 35.541 − 398 =
36. 36.499 − 148 =
37. 37.369 − 198 =
38. 38.725 − 699 =
39. 39.896 − 298 =
40. 40.939 − 199 =

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