Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 258 · 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. 1.645 − 448 =
2. 2.293 − 197 =
3. 3.295 − 197 =
4. 4.785 − 699 =
5. 5.838 − 199 =
6. 6.492 − 397 =
7. 7.999 − 497 =
8. 8.568 − 298 =
9. 9.768 − 328 =
10. 10.644 − 198 =
11. 11.837 − 588 =
12. 12.926 − 609 =
13. 13.679 − 197 =
14. 14.826 − 117 =
15. 15.786 − 338 =
16. 16.980 − 348 =
17. 17.751 − 499 =
18. 18.277 − 117 =
19. 19.466 − 397 =
20. 20.741 − 149 =
21. 21.821 − 699 =
22. 22.983 − 199 =
23. 23.544 − 428 =
24. 24.137 − 118 =
25. 25.942 − 198 =
26. 26.604 − 588 =
27. 27.858 − 179 =
28. 28.951 − 388 =
29. 29.346 − 329 =
30. 30.801 − 299 =
31. 31.915 − 238 =
32. 32.408 − 199 =
33. 33.400 − 297 =
34. 34.765 − 669 =
35. 35.578 − 297 =
36. 36.767 − 699 =
37. 37.814 − 648 =
38. 38.832 − 797 =
39. 39.555 − 397 =
40. 40.533 − 499 =

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