Addition
The only formal algorithm I want you to know in addition to the standard algorithm is the expanded algorithm. Please practice the expanded algorithm for these problems:
1. 268+372
2. 485+791
3. 468 + 756
You should also know how to solve two digit addition problems by rounding and compensating and by using the make 10 strategy. Please use a. the rounding and compensating (friendly numbers) strategy and b. the make 10 strategy for these problems:
4. 48 + 87
5. 69 + 72
6. 32+49
Subtraction
I want you to be able to use the trade-first strategy for subtraction, and be able to figure out the exchanges in both left to right and right to left order. For each of these problems, solve by the trade first strategy a. writing the trades in left to right order, and b. writing the trades in right to left order.
7. 743 - 297
8. 3429 - 1735
9. 406 - 328
You should also be able to use the negative numbers strategy, since that's one that is natural to a significant number of children. Please use the negative numbers strategy to solve each of these problems:
10. 84 - 27
11. 723 - 176
12. 748 - 281
And finally, I would like you to practice the round and compensate (friendly numbers) strategy for these problems:
13. 90 - 28
14. 70 - 32
15. 92 - 28
16. 69 - 32