Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 613 · 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. 1.703 − 298 =
2. 2.656 − 399 =
3. 3.564 − 297 =
4. 4.252 − 197 =
5. 5.700 − 498 =
6. 6.389 − 359 =
7. 7.518 − 298 =
8. 8.411 − 288 =
9. 9.274 − 117 =
10. 10.990 − 429 =
11. 11.518 − 247 =
12. 12.282 − 209 =
13. 13.680 − 339 =
14. 14.623 − 547 =
15. 15.407 − 198 =
16. 16.829 − 797 =
17. 17.556 − 478 =
18. 18.894 − 599 =
19. 19.822 − 497 =
20. 20.933 − 387 =
21. 21.712 − 699 =
22. 22.819 − 459 =
23. 23.441 − 199 =
24. 24.626 − 528 =
25. 25.709 − 639 =
26. 26.762 − 379 =
27. 27.847 − 597 =
28. 28.812 − 697 =
29. 29.577 − 539 =
30. 30.891 − 199 =
31. 31.396 − 198 =
32. 32.669 − 489 =
33. 33.535 − 378 =
34. 34.791 − 697 =
35. 35.617 − 599 =
36. 36.851 − 798 =
37. 37.729 − 197 =
38. 38.679 − 517 =
39. 39.880 − 799 =
40. 40.523 − 357 =

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