Use the model to find the missing number in the pair of
equivalent expressions.
15 + 9 = ?(5+3)
What number is missing from the expression?
![Use the model to find the missing number in the pair of equivalent expressions 15 9 53 What number is missing from the expression class=](https://us-static.z-dn.net/files/d0d/3f90276a024f7d27031d8c6de579151c.png)