Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 117 · 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. 1.354 − 197 =
2. 2.842 − 298 =
3. 3.743 − 199 =
4. 4.599 − 299 =
5. 5.652 − 519 =
6. 6.520 − 428 =
7. 7.802 − 299 =
8. 8.291 − 207 =
9. 9.456 − 197 =
10. 10.868 − 797 =
11. 11.555 − 199 =
12. 12.727 − 517 =
13. 13.695 − 648 =
14. 14.975 − 659 =
15. 15.938 − 798 =
16. 16.965 − 658 =
17. 17.836 − 699 =
18. 18.701 − 499 =
19. 19.606 − 368 =
20. 20.646 − 157 =
21. 21.777 − 578 =
22. 22.996 − 798 =
23. 23.588 − 469 =
24. 24.283 − 199 =
25. 25.816 − 798 =
26. 26.615 − 229 =
27. 27.577 − 507 =
28. 28.681 − 397 =
29. 29.923 − 617 =
30. 30.404 − 259 =
31. 31.889 − 598 =
32. 32.683 − 199 =
33. 33.832 − 797 =
34. 34.963 − 798 =
35. 35.579 − 378 =
36. 36.894 − 597 =
37. 37.732 − 538 =
38. 38.979 − 379 =
39. 39.460 − 397 =
40. 40.758 − 637 =

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