Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 332 · 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. 1.986 − 697 =
2. 2.927 − 679 =
3. 3.964 − 798 =
4. 4.496 − 398 =
5. 5.240 − 199 =
6. 6.776 − 339 =
7. 7.752 − 639 =
8. 8.542 − 298 =
9. 9.944 − 418 =
10. 10.291 − 199 =
11. 11.884 − 399 =
12. 12.990 − 797 =
13. 13.533 − 497 =
14. 14.647 − 359 =
15. 15.800 − 298 =
16. 16.858 − 428 =
17. 17.983 − 797 =
18. 18.363 − 199 =
19. 19.825 − 387 =
20. 20.679 − 308 =
21. 21.240 − 198 =
22. 22.539 − 189 =
23. 23.806 − 637 =
24. 24.639 − 347 =
25. 25.571 − 527 =
26. 26.370 − 309 =
27. 27.357 − 297 =
28. 28.818 − 798 =
29. 29.429 − 398 =
30. 30.999 − 458 =
31. 31.608 − 579 =
32. 32.538 − 397 =
33. 33.964 − 179 =
34. 34.360 − 197 =
35. 35.685 − 187 =
36. 36.989 − 439 =
37. 37.961 − 348 =
38. 38.941 − 389 =
39. 39.872 − 647 =
40. 40.964 − 797 =

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