3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 566 · 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. 1.757 + 329 =
2. 2.565 − 318 =
3. 3.567 − 153 =
4. 4.479 + 431 =
5. 5.874 − 664 =
6. 6.596 + 142 =
7. 7.482 + 355 =
8. 8.484 + 309 =
9. 9.746 + 159 =
10. 10.980 − 674 =
11. 11.424 − 208 =
12. 12.333 + 428 =
13. 13.791 − 269 =
14. 14.502 + 615 =
15. 15.744 − 299 =
16. 16.682 − 142 =
17. 17.443 − 256 =
18. 18.142 + 421 =
19. 19.573 + 137 =
20. 20.646 − 419 =
21. 21.582 − 359 =
22. 22.526 + 239 =
23. 23.669 − 555 =
24. 24.480 − 241 =
25. 25.568 + 273 =
26. 26.613 − 194 =
27. 27.626 + 621 =
28. 28.863 − 639 =
29. 29.443 − 235 =
30. 30.243 + 529 =
31. 31.692 + 632 =
32. 32.751 − 561 =
33. 33.560 + 329 =
34. 34.877 − 284 =
35. 35.340 + 531 =
36. 36.946 − 678 =
37. 37.571 + 171 =
38. 38.412 + 603 =
39. 39.706 + 251 =
40. 40.653 + 364 =

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