Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 741 · 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. 1.575 − 217 =
2. 2.474 − 207 =
3. 3.466 − 398 =
4. 4.929 − 197 =
5. 5.914 − 198 =
6. 6.241 − 198 =
7. 7.594 − 199 =
8. 8.697 − 297 =
9. 9.604 − 199 =
10. 10.628 − 598 =
11. 11.657 − 597 =
12. 12.849 − 247 =
13. 13.779 − 397 =
14. 14.342 − 327 =
15. 15.359 − 298 =
16. 16.898 − 119 =
17. 17.849 − 697 =
18. 18.806 − 397 =
19. 19.602 − 499 =
20. 20.822 − 798 =
21. 21.892 − 399 =
22. 22.666 − 288 =
23. 23.827 − 799 =
24. 24.835 − 569 =
25. 25.924 − 297 =
26. 26.566 − 547 =
27. 27.628 − 498 =
28. 28.783 − 697 =
29. 29.512 − 499 =
30. 30.980 − 397 =
31. 31.629 − 608 =
32. 32.905 − 799 =
33. 33.370 − 149 =
34. 34.500 − 197 =
35. 35.907 − 797 =
36. 36.845 − 399 =
37. 37.786 − 438 =
38. 38.607 − 247 =
39. 39.690 − 397 =
40. 40.769 − 198 =

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