This Problem Set is a part of the Lesson 17, Unit 1, Grade 1. In this lesson, students use linking cubes to write expressions and to demonstrate that they are equivalent by using the equal sign. For example, they divide one group of 5 into 3 and 2, and another group of 5 into 4 and 1, and write the equation 3 + 2 = 4 + 1.
