Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 614 · 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. 1.507 − 299 =
2. 2.521 − 299 =
3. 3.588 − 498 =
4. 4.248 − 229 =
5. 5.624 − 219 =
6. 6.839 − 278 =
7. 7.993 − 648 =
8. 8.898 − 517 =
9. 9.731 − 499 =
10. 10.717 − 599 =
11. 11.681 − 619 =
12. 12.853 − 698 =
13. 13.453 − 369 =
14. 14.389 − 298 =
15. 15.714 − 379 =
16. 16.564 − 398 =
17. 17.782 − 407 =
18. 18.700 − 339 =
19. 19.774 − 548 =
20. 20.755 − 637 =
21. 21.983 − 299 =
22. 22.970 − 297 =
23. 23.328 − 259 =
24. 24.767 − 498 =
25. 25.648 − 147 =
26. 26.385 − 329 =
27. 27.658 − 379 =
28. 28.941 − 177 =
29. 29.746 − 407 =
30. 30.409 − 327 =
31. 31.343 − 198 =
32. 32.938 − 698 =
33. 33.650 − 569 =
34. 34.721 − 699 =
35. 35.280 − 199 =
36. 36.772 − 429 =
37. 37.836 − 297 =
38. 38.745 − 498 =
39. 39.636 − 599 =
40. 40.825 − 699 =

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