Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 936 · 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. 1.375 − 198 =
2. 2.956 − 598 =
3. 3.751 − 498 =
4. 4.528 − 399 =
5. 5.842 − 498 =
6. 6.905 − 278 =
7. 7.943 − 799 =
8. 8.748 − 697 =
9. 9.793 − 399 =
10. 10.485 − 197 =
11. 11.897 − 399 =
12. 12.674 − 479 =
13. 13.841 − 798 =
14. 14.872 − 799 =
15. 15.518 − 467 =
16. 16.724 − 149 =
17. 17.563 − 459 =
18. 18.570 − 308 =
19. 19.864 − 649 =
20. 20.634 − 299 =
21. 21.530 − 407 =
22. 22.640 − 409 =
23. 23.812 − 199 =
24. 24.917 − 577 =
25. 25.216 − 179 =
26. 26.314 − 129 =
27. 27.789 − 509 =
28. 28.825 − 797 =
29. 29.269 − 167 =
30. 30.946 − 399 =
31. 31.973 − 287 =
32. 32.985 − 797 =
33. 33.695 − 477 =
34. 34.226 − 198 =
35. 35.955 − 397 =
36. 36.955 − 797 =
37. 37.496 − 299 =
38. 38.403 − 358 =
39. 39.948 − 697 =
40. 40.493 − 387 =

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