Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 796 · 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. 1.966 − 797 =
2. 2.946 − 497 =
3. 3.821 − 538 =
4. 4.696 − 569 =
5. 5.553 − 197 =
6. 6.988 − 679 =
7. 7.986 − 197 =
8. 8.798 − 307 =
9. 9.656 − 397 =
10. 10.843 − 199 =
11. 11.974 − 399 =
12. 12.941 − 597 =
13. 13.781 − 429 =
14. 14.957 − 677 =
15. 15.363 − 219 =
16. 16.266 − 209 =
17. 17.815 − 797 =
18. 18.759 − 397 =
19. 19.563 − 458 =
20. 20.443 − 249 =
21. 21.860 − 798 =
22. 22.389 − 197 =
23. 23.404 − 299 =
24. 24.608 − 497 =
25. 25.585 − 197 =
26. 26.895 − 297 =
27. 27.849 − 297 =
28. 28.252 − 199 =
29. 29.947 − 199 =
30. 30.310 − 228 =
31. 31.810 − 597 =
32. 32.500 − 398 =
33. 33.546 − 347 =
34. 34.906 − 297 =
35. 35.664 − 239 =
36. 36.831 − 597 =
37. 37.958 − 797 =
38. 38.759 − 369 =
39. 39.609 − 498 =
40. 40.815 − 498 =

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