3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 995 · 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. 1.700 + 361 =
2. 2.812 − 119 =
3. 3.723 + 573 =
4. 4.650 + 615 =
5. 5.663 − 128 =
6. 6.320 + 201 =
7. 7.147 + 169 =
8. 8.464 + 311 =
9. 9.760 + 191 =
10. 10.223 + 374 =
11. 11.789 − 346 =
12. 12.584 − 222 =
13. 13.429 + 598 =
14. 14.705 − 151 =
15. 15.528 − 341 =
16. 16.531 − 152 =
17. 17.757 + 239 =
18. 18.692 + 201 =
19. 19.888 − 482 =
20. 20.142 + 224 =
21. 21.585 − 316 =
22. 22.859 − 686 =
23. 23.749 − 461 =
24. 24.706 + 462 =
25. 25.410 + 271 =
26. 26.557 − 132 =
27. 27.260 + 482 =
28. 28.508 + 659 =
29. 29.536 − 319 =
30. 30.765 − 551 =
31. 31.650 − 315 =
32. 32.644 + 423 =
33. 33.144 + 408 =
34. 34.385 + 549 =
35. 35.617 − 297 =
36. 36.351 + 581 =
37. 37.676 + 344 =
38. 38.944 − 528 =
39. 39.216 + 305 =
40. 40.201 + 591 =

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