Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 469 · 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. 1.934 − 529 =
2. 2.431 − 397 =
3. 3.677 − 397 =
4. 4.999 − 517 =
5. 5.454 − 397 =
6. 6.595 − 157 =
7. 7.362 − 227 =
8. 8.912 − 798 =
9. 9.954 − 657 =
10. 10.301 − 227 =
11. 11.799 − 297 =
12. 12.490 − 228 =
13. 13.729 − 499 =
14. 14.797 − 497 =
15. 15.725 − 599 =
16. 16.793 − 398 =
17. 17.644 − 188 =
18. 18.638 − 509 =
19. 19.662 − 459 =
20. 20.428 − 208 =
21. 21.700 − 457 =
22. 22.500 − 268 =
23. 23.942 − 697 =
24. 24.701 − 647 =
25. 25.726 − 127 =
26. 26.849 − 597 =
27. 27.815 − 799 =
28. 28.638 − 369 =
29. 29.910 − 597 =
30. 30.383 − 299 =
31. 31.905 − 378 =
32. 32.583 − 199 =
33. 33.981 − 799 =
34. 34.460 − 389 =
35. 35.705 − 468 =
36. 36.983 − 699 =
37. 37.854 − 799 =
38. 38.554 − 299 =
39. 39.434 − 198 =
40. 40.614 − 388 =

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths