Practice:
Think addition and fact families questions
1. Explain how to use think addition using a part-whole diagram or math mountain to figure out 14-6=__
2. Write the missing number fact family for 12-7=___
3. Write the fact family for 12-8=4
4. Draw an open number line diagram that would show the think addition strategy for 14-9=
5. Explain two reasons why think addition is a good strategy for subtraction.
Basic facts drill questions
6. Describe two of Rathmell's recommendations for drill exercises on the math basic facts.
7. Write a cluster of 10 problems for the "use doubles to add" strategy
Review of strategies questions
8. What does it mean when we say that addition is commutative?
9. For each of these strategies, choose a math fact for which it is an efficient strategy, and show how to use the strategy to compute the fact. For the *-ed strategies, draw an open number line diagram for the strategy as well as writing number sentences.
a. count on to add
b. count back to subtract
c. count up to subtract
d. use doubles to add
e. make ten to add *
f. build up through ten to subtract *
g. back down through ten to subtract *
10. For each of the math facts problems on the left, tell all of the strategies on the right that would be efficient ways to compute it.
A. 7+8 B. 6+9 C. 2+7 D. 3+8 E. 14-8 F. 9-7 G. 8-2 H. 14-6 |
a. count on to add b. count back to subtract c. count up to subtract d. use doubles to add e. make ten to add f. build up through ten to subtract g. back down through ten to subtract h. think addition to subtract |
11. Describe the set of facts for which each of these strategies is efficient:
a. count on to add
b. count back to subtract
c. count up to subtract
d. use doubles to add
e. make ten to add
f. build up through ten to subtract
g. back down through ten to subtract