Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 929 · 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. 1.829 − 798 =
2. 2.499 − 368 =
3. 3.756 − 197 =
4. 4.874 − 798 =
5. 5.861 − 797 =
6. 6.614 − 248 =
7. 7.929 − 479 =
8. 8.649 − 497 =
9. 9.755 − 199 =
10. 10.631 − 298 =
11. 11.557 − 157 =
12. 12.635 − 299 =
13. 13.816 − 597 =
14. 14.932 − 297 =
15. 15.794 − 497 =
16. 16.838 − 297 =
17. 17.382 − 298 =
18. 18.230 − 127 =
19. 19.578 − 297 =
20. 20.877 − 799 =
21. 21.519 − 319 =
22. 22.669 − 599 =
23. 23.810 − 579 =
24. 24.868 − 198 =
25. 25.787 − 569 =
26. 26.898 − 528 =
27. 27.956 − 599 =
28. 28.617 − 199 =
29. 29.653 − 529 =
30. 30.513 − 398 =
31. 31.870 − 479 =
32. 32.378 − 198 =
33. 33.253 − 198 =
34. 34.687 − 669 =
35. 35.868 − 498 =
36. 36.978 − 617 =
37. 37.504 − 157 =
38. 38.639 − 589 =
39. 39.746 − 397 =
40. 40.896 − 297 =

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