Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 351 · 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. 1.747 − 498 =
2. 2.367 − 249 =
3. 3.876 − 529 =
4. 4.497 − 198 =
5. 5.847 − 797 =
6. 6.849 − 398 =
7. 7.773 − 197 =
8. 8.521 − 189 =
9. 9.866 − 498 =
10. 10.634 − 549 =
11. 11.509 − 478 =
12. 12.752 − 197 =
13. 13.588 − 439 =
14. 14.297 − 198 =
15. 15.894 − 298 =
16. 16.853 − 197 =
17. 17.575 − 197 =
18. 18.920 − 599 =
19. 19.867 − 599 =
20. 20.575 − 397 =
21. 21.689 − 358 =
22. 22.594 − 498 =
23. 23.832 − 797 =
24. 24.977 − 599 =
25. 25.596 − 489 =
26. 26.541 − 499 =
27. 27.742 − 497 =
28. 28.748 − 499 =
29. 29.527 − 398 =
30. 30.562 − 209 =
31. 31.778 − 599 =
32. 32.830 − 698 =
33. 33.530 − 498 =
34. 34.997 − 799 =
35. 35.939 − 189 =
36. 36.289 − 199 =
37. 37.219 − 199 =
38. 38.722 − 497 =
39. 39.700 − 198 =
40. 40.489 − 298 =

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