Solve put together/take apart with addend unknown math stories.

In this lesson, students solve "put together/take apart with addend unknown" problems (for example, "There were 8 apples in a row. 5 of them were red, and the rest were green. How many apples were green?"). They use number bonds and addition and subtraction equations (such as 5 + ___ = 8 and 8 - 5 = ___) to represent and solve each problem.