3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 716 · 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. 1.440 + 647 =
2. 2.915 − 561 =
3. 3.649 − 113 =
4. 4.765 − 312 =
5. 5.577 − 284 =
6. 6.426 + 572 =
7. 7.732 − 559 =
8. 8.661 − 357 =
9. 9.622 − 365 =
10. 10.481 + 676 =
11. 11.197 + 302 =
12. 12.774 + 675 =
13. 13.737 + 526 =
14. 14.958 − 141 =
15. 15.684 + 566 =
16. 16.715 − 398 =
17. 17.583 + 131 =
18. 18.870 − 493 =
19. 19.306 + 687 =
20. 20.584 − 329 =
21. 21.870 − 425 =
22. 22.668 − 151 =
23. 23.782 − 334 =
24. 24.747 + 287 =
25. 25.374 + 663 =
26. 26.452 − 187 =
27. 27.882 − 668 =
28. 28.750 + 604 =
29. 29.617 + 565 =
30. 30.347 + 369 =
31. 31.924 − 122 =
32. 32.178 + 201 =
33. 33.640 − 154 =
34. 34.659 − 536 =
35. 35.891 − 765 =
36. 36.455 − 155 =
37. 37.308 + 518 =
38. 38.805 − 665 =
39. 39.461 − 313 =
40. 40.132 + 415 =

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