3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 591 · 40 questions

How to do it in your head (Hundreds first): Keep the first number as it is and split the second into hundreds, tens and ones. Add (or take away) the hundreds first, then the tens. Finish with the ones — bridge through a ten if you need to.

1. 1.587 + 589 =
2. 2.499 − 379 =
3. 3.186 + 554 =
4. 4.617 + 673 =
5. 5.492 + 146 =
6. 6.360 + 132 =
7. 7.391 + 279 =
8. 8.364 + 589 =
9. 9.520 + 341 =
10. 10.436 − 256 =
11. 11.642 − 461 =
12. 12.755 + 192 =
13. 13.825 − 565 =
14. 14.864 − 246 =
15. 15.941 − 201 =
16. 16.316 + 281 =
17. 17.965 − 706 =
18. 18.639 − 118 =
19. 19.670 + 422 =
20. 20.523 + 183 =
21. 21.953 − 826 =
22. 22.274 + 544 =
23. 23.470 − 137 =
24. 24.161 + 172 =
25. 25.432 − 218 =
26. 26.660 − 296 =
27. 27.715 − 146 =
28. 28.613 + 302 =
29. 29.466 + 366 =
30. 30.686 + 466 =
31. 31.272 + 653 =
32. 32.740 − 421 =
33. 33.549 − 149 =
34. 34.224 + 526 =
35. 35.548 + 316 =
36. 36.619 + 268 =
37. 37.770 − 501 =
38. 38.611 − 116 =
39. 39.604 − 333 =
40. 40.718 − 343 =

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