Collecting Like Terms
I use a similar strategy when I am explaining how to add like terms. For example, if we have an expression such as 6x2 + 2x4 - 2x2 + 7 + 3x2- 3 and the goal is to combine like terms, I first ask three students to name their favorite fruit. If I get answers such as apples, oranges and bananas, I first rewrite this expression as 6 apples + 2 oranges – 2 apples + 7 bananas + 3 oranges - 3 bananas. Then I ask them to evaluate how many fruits of each kind are left. Most can figure this out as 4 apples + 5 oranges + 4 bananas.
Then I tell students that in math we also have different kinds of fruits but they have mathematical names such as x4, x2 and just plain numbers. They are then usually able to make the connection and get the right answer.