Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 444 · 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. 1.820 − 598 =
2. 2.946 − 399 =
3. 3.679 − 499 =
4. 4.390 − 198 =
5. 5.967 − 799 =
6. 6.545 − 508 =
7. 7.812 − 799 =
8. 8.831 − 629 =
9. 9.482 − 399 =
10. 10.592 − 297 =
11. 11.709 − 298 =
12. 12.747 − 297 =
13. 13.527 − 499 =
14. 14.637 − 397 =
15. 15.568 − 248 =
16. 16.620 − 597 =
17. 17.420 − 357 =
18. 18.462 − 447 =
19. 19.732 − 697 =
20. 20.540 − 197 =
21. 21.747 − 597 =
22. 22.659 − 258 =
23. 23.522 − 198 =
24. 24.673 − 317 =
25. 25.619 − 599 =
26. 26.803 − 699 =
27. 27.859 − 178 =
28. 28.785 − 457 =
29. 29.755 − 649 =
30. 30.361 − 207 =
31. 31.727 − 697 =
32. 32.454 − 258 =
33. 33.708 − 297 =
34. 34.557 − 487 =
35. 35.747 − 468 =
36. 36.663 − 497 =
37. 37.723 − 698 =
38. 38.774 − 189 =
39. 39.413 − 167 =
40. 40.349 − 298 =

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