Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 806 · 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. 1.939 − 208 =
2. 2.977 − 648 =
3. 3.740 − 677 =
4. 4.654 − 198 =
5. 5.977 − 798 =
6. 6.423 − 129 =
7. 7.483 − 358 =
8. 8.282 − 199 =
9. 9.359 − 197 =
10. 10.977 − 797 =
11. 11.839 − 207 =
12. 12.713 − 398 =
13. 13.335 − 267 =
14. 14.337 − 228 =
15. 15.890 − 798 =
16. 16.750 − 308 =
17. 17.548 − 398 =
18. 18.858 − 128 =
19. 19.852 − 799 =
20. 20.810 − 509 =
21. 21.639 − 317 =
22. 22.913 − 797 =
23. 23.869 − 428 =
24. 24.309 − 269 =
25. 25.833 − 397 =
26. 26.533 − 447 =
27. 27.989 − 397 =
28. 28.430 − 198 =
29. 29.629 − 297 =
30. 30.409 − 169 =
31. 31.617 − 399 =
32. 32.245 − 119 =
33. 33.808 − 697 =
34. 34.976 − 298 =
35. 35.612 − 127 =
36. 36.929 − 367 =
37. 37.480 − 317 =
38. 38.734 − 698 =
39. 39.947 − 798 =
40. 40.946 − 697 =

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