The Birds
9 birds land on a fence. Some more come.
Now there are 18 birds on the fence. How
many birds came to the fence?
Max solved the problem. Answer the items
below to check his thinking. Use pictures,
words, or equations to explain.
2. MP.3 Explain Max says that he
can use a doubles fact to solve this
problem. Do you agree? Explain.

3. MP.4 Model How could Max have used
words or drawings to show the problem?