Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 21 · 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. 1.334 − 249 =
2. 2.983 − 497 =
3. 3.745 − 599 =
4. 4.697 − 268 =
5. 5.900 − 628 =
6. 6.725 − 558 =
7. 7.877 − 598 =
8. 8.520 − 497 =
9. 9.530 − 199 =
10. 10.825 − 697 =
11. 11.386 − 298 =
12. 12.993 − 699 =
13. 13.914 − 259 =
14. 14.740 − 567 =
15. 15.638 − 528 =
16. 16.305 − 288 =
17. 17.710 − 497 =
18. 18.539 − 399 =
19. 19.583 − 449 =
20. 20.732 − 597 =
21. 21.876 − 328 =
22. 22.774 − 367 =
23. 23.703 − 499 =
24. 24.894 − 498 =
25. 25.786 − 498 =
26. 26.746 − 199 =
27. 27.449 − 159 =
28. 28.510 − 489 =
29. 29.524 − 488 =
30. 30.847 − 799 =
31. 31.733 − 488 =
32. 32.632 − 329 =
33. 33.354 − 219 =
34. 34.805 − 679 =
35. 35.599 − 498 =
36. 36.957 − 798 =
37. 37.888 − 798 =
38. 38.709 − 197 =
39. 39.832 − 598 =
40. 40.584 − 439 =

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