3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 555 · 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. 1.697 − 211 =
2. 2.527 − 134 =
3. 3.643 + 554 =
4. 4.710 − 208 =
5. 5.950 − 287 =
6. 6.739 − 161 =
7. 7.506 − 284 =
8. 8.880 − 442 =
9. 9.786 + 538 =
10. 10.700 + 355 =
11. 11.288 + 557 =
12. 12.850 − 174 =
13. 13.795 − 151 =
14. 14.250 + 456 =
15. 15.149 + 155 =
16. 16.465 − 217 =
17. 17.505 − 363 =
18. 18.182 + 309 =
19. 19.666 − 128 =
20. 20.510 + 645 =
21. 21.425 − 205 =
22. 22.705 + 183 =
23. 23.539 + 221 =
24. 24.152 + 309 =
25. 25.437 − 134 =
26. 26.546 + 151 =
27. 27.485 − 145 =
28. 28.520 − 304 =
29. 29.609 − 374 =
30. 30.730 − 222 =
31. 31.587 + 231 =
32. 32.398 + 386 =
33. 33.923 − 734 =
34. 34.785 + 209 =
35. 35.293 + 309 =
36. 36.729 − 226 =
37. 37.773 + 254 =
38. 38.275 + 607 =
39. 39.409 + 359 =
40. 40.916 − 636 =

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