Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 652 · 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. 1.627 − 198 =
2. 2.706 − 598 =
3. 3.735 − 699 =
4. 4.282 − 178 =
5. 5.543 − 329 =
6. 6.667 − 137 =
7. 7.446 − 397 =
8. 8.546 − 499 =
9. 9.595 − 498 =
10. 10.686 − 397 =
11. 11.959 − 279 =
12. 12.623 − 198 =
13. 13.886 − 697 =
14. 14.810 − 277 =
15. 15.393 − 197 =
16. 16.605 − 589 =
17. 17.802 − 697 =
18. 18.386 − 169 =
19. 19.668 − 329 =
20. 20.641 − 297 =
21. 21.846 − 678 =
22. 22.743 − 259 =
23. 23.742 − 498 =
24. 24.463 − 309 =
25. 25.999 − 279 =
26. 26.497 − 239 =
27. 27.863 − 398 =
28. 28.636 − 598 =
29. 29.907 − 529 =
30. 30.739 − 549 =
31. 31.751 − 237 =
32. 32.635 − 487 =
33. 33.386 − 298 =
34. 34.745 − 647 =
35. 35.896 − 198 =
36. 36.641 − 199 =
37. 37.855 − 198 =
38. 38.644 − 579 =
39. 39.753 − 667 =
40. 40.611 − 559 =

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