Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 512 · 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. 1.601 − 399 =
2. 2.535 − 398 =
3. 3.863 − 299 =
4. 4.852 − 599 =
5. 5.912 − 799 =
6. 6.380 − 299 =
7. 7.507 − 299 =
8. 8.693 − 629 =
9. 9.919 − 647 =
10. 10.909 − 797 =
11. 11.485 − 457 =
12. 12.993 − 799 =
13. 13.674 − 598 =
14. 14.553 − 487 =
15. 15.632 − 599 =
16. 16.573 − 199 =
17. 17.980 − 198 =
18. 18.986 − 599 =
19. 19.915 − 797 =
20. 20.619 − 298 =
21. 21.996 − 799 =
22. 22.505 − 208 =
23. 23.942 − 288 =
24. 24.763 − 597 =
25. 25.296 − 208 =
26. 26.673 − 297 =
27. 27.746 − 527 =
28. 28.717 − 579 =
29. 29.711 − 639 =
30. 30.479 − 397 =
31. 31.835 − 199 =
32. 32.546 − 299 =
33. 33.806 − 299 =
34. 34.659 − 599 =
35. 35.726 − 699 =
36. 36.653 − 588 =
37. 37.738 − 199 =
38. 38.521 − 399 =
39. 39.334 − 247 =
40. 40.768 − 697 =

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