3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 666 · 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. 1.916 − 762 =
2. 2.629 + 193 =
3. 3.493 − 351 =
4. 4.350 + 191 =
5. 5.758 + 541 =
6. 6.533 − 236 =
7. 7.655 − 153 =
8. 8.763 + 469 =
9. 9.486 − 151 =
10. 10.798 − 122 =
11. 11.571 − 372 =
12. 12.464 − 143 =
13. 13.179 + 202 =
14. 14.670 − 208 =
15. 15.783 + 345 =
16. 16.603 + 442 =
17. 17.540 + 563 =
18. 18.535 − 307 =
19. 19.606 + 288 =
20. 20.760 + 591 =
21. 21.314 + 217 =
22. 22.586 + 437 =
23. 23.378 + 616 =
24. 24.690 − 506 =
25. 25.929 − 357 =
26. 26.510 − 382 =
27. 27.604 + 279 =
28. 28.592 − 324 =
29. 29.527 − 347 =
30. 30.769 − 167 =
31. 31.905 − 746 =
32. 32.490 − 151 =
33. 33.489 − 141 =
34. 34.251 + 122 =
35. 35.433 + 581 =
36. 36.591 − 285 =
37. 37.573 − 288 =
38. 38.535 + 361 =
39. 39.528 + 605 =
40. 40.723 − 211 =

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