Lesson objective: Understand that an equation will be true if both sides of the equals sign have the same value, and false if the two sides have differing values.

Students bring prior knowledge of the meaning of the equals sign from Grade 1, Unit 9, 1.OA.D.7. This prior knowledge is extended to include determining if an equation is true or false as students calculate and compare values within addition and subtraction equations. A conceptual challenge students may encounter is working with equations with multiple numbers on both sides of the equals sign, as well as seeing both addition and subtraction within the same equation.

The concept is developed through work with counters, which allow students to visually count and compare the value of each side of the equals sign.

This work helps students deepen their understanding of equivalence because while determining if equations are true or false, students will be comparing values in terms of equal or not equal.

Students engage in Mathematical Practice #2 (reason abstractly and quantitatively) as they compare the two sides of an equation to determine if the equation is true or false. Before students typically only saw true equations, with two parts on one side of the equals sign and the sum or difference on the opposite side. This task will guide students away from assuming one side of the equation is the answer to an operation, while giving them an authentic contextual situation.

**Key vocabulary:**

- amount
- determine
- equal
- equals sign
- equation
- false
- model
- represent
- true
- value

**Special materials needed:**

- manipulatives, such as counters or cubes