Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 626 · 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. 1.396 − 238 =
2. 2.274 − 199 =
3. 3.955 − 299 =
4. 4.679 − 299 =
5. 5.965 − 299 =
6. 6.829 − 169 =
7. 7.513 − 369 =
8. 8.816 − 199 =
9. 9.915 − 699 =
10. 10.830 − 797 =
11. 11.769 − 449 =
12. 12.643 − 599 =
13. 13.746 − 697 =
14. 14.520 − 297 =
15. 15.807 − 399 =
16. 16.774 − 699 =
17. 17.635 − 287 =
18. 18.515 − 199 =
19. 19.359 − 297 =
20. 20.975 − 598 =
21. 21.647 − 618 =
22. 22.647 − 278 =
23. 23.716 − 177 =
24. 24.620 − 539 =
25. 25.993 − 297 =
26. 26.442 − 398 =
27. 27.864 − 598 =
28. 28.842 − 797 =
29. 29.863 − 649 =
30. 30.809 − 199 =
31. 31.906 − 599 =
32. 32.701 − 328 =
33. 33.754 − 548 =
34. 34.509 − 298 =
35. 35.835 − 597 =
36. 36.281 − 257 =
37. 37.844 − 369 =
38. 38.416 − 189 =
39. 39.990 − 399 =
40. 40.572 − 497 =

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