Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 872 · 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. 1.978 − 199 =
2. 2.760 − 498 =
3. 3.334 − 129 =
4. 4.645 − 297 =
5. 5.733 − 537 =
6. 6.433 − 299 =
7. 7.708 − 398 =
8. 8.951 − 498 =
9. 9.886 − 597 =
10. 10.583 − 399 =
11. 11.844 − 519 =
12. 12.813 − 798 =
13. 13.641 − 397 =
14. 14.721 − 447 =
15. 15.836 − 797 =
16. 16.595 − 118 =
17. 17.881 − 469 =
18. 18.245 − 199 =
19. 19.602 − 459 =
20. 20.505 − 299 =
21. 21.841 − 797 =
22. 22.851 − 209 =
23. 23.910 − 419 =
24. 24.615 − 597 =
25. 25.819 − 589 =
26. 26.937 − 797 =
27. 27.814 − 247 =
28. 28.914 − 529 =
29. 29.878 − 669 =
30. 30.703 − 198 =
31. 31.920 − 298 =
32. 32.669 − 497 =
33. 33.906 − 399 =
34. 34.827 − 598 =
35. 35.637 − 428 =
36. 36.407 − 119 =
37. 37.760 − 398 =
38. 38.402 − 347 =
39. 39.431 − 199 =
40. 40.542 − 297 =

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