To solve problem A, should you count on from 9 or count back from 9?
Count back from 9.
When you count back from 9 five times, what is the answer?
4
How can you write problem A as an addition problem?
5 + \text{?} = 9
How many times do you count on from 5 to get to 9?
Look at problem B. What problem can you write tofind the missing number?
12-8=\;?, because addition and subtraction are related.
When you count back from 12 eight times, where do you land?
Look at problem C. What is the sum?
10
Look at problem D. What is the sum?
9