This is a partner activity. One student gets one side of the tree, and the other student gets the other side.
They work independently(preferably not side by side) throughout the 8 problems.
After they are both finished, they should be able to put the trees together and it should be colored identically on each side. If not, one of them made a mistake. They will then go back and figure out which one made the error.
This activity gets the students talking and problem solving.
My students loved this activity!