Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 536 · 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. 1.963 − 549 =
2. 2.946 − 598 =
3. 3.798 − 258 =
4. 4.698 − 358 =
5. 5.959 − 398 =
6. 6.533 − 449 =
7. 7.898 − 699 =
8. 8.699 − 397 =
9. 9.957 − 298 =
10. 10.520 − 418 =
11. 11.712 − 199 =
12. 12.766 − 597 =
13. 13.798 − 199 =
14. 14.666 − 299 =
15. 15.578 − 399 =
16. 16.451 − 308 =
17. 17.907 − 197 =
18. 18.992 − 798 =
19. 19.682 − 259 =
20. 20.527 − 339 =
21. 21.770 − 199 =
22. 22.677 − 629 =
23. 23.653 − 598 =
24. 24.779 − 608 =
25. 25.540 − 298 =
26. 26.627 − 397 =
27. 27.509 − 199 =
28. 28.481 − 217 =
29. 29.605 − 229 =
30. 30.957 − 197 =
31. 31.965 − 797 =
32. 32.973 − 499 =
33. 33.970 − 198 =
34. 34.932 − 377 =
35. 35.793 − 397 =
36. 36.860 − 697 =
37. 37.874 − 449 =
38. 38.870 − 198 =
39. 39.912 − 697 =
40. 40.522 − 198 =

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