Lesson objective: Use the properties of multiplication and the relationship between multiplication and division to solve equations with an unknown.

Students bring prior knowledge of the properties of multiplication from 3.OA.B.5. This prior knowledge is extended to including the associative property as another strategy students can use to help them solve multiplication problems. A conceptual challenge students may encounter is understanding that the distributive breaks apart one factor into two addends while using the associative property as a strategy may involve breaking apart a factor into two new factors.

The concept is developed through work with area models, which can be manipulated to provide a visual representation of each property.

This work helps students deepen their understanding of equivalence because the properties can be used strategically to rewrite equations into an equivalent equation with friendlier numbers.

Students engage in Mathematical Practice 6 (attend to precision) as they clearly and effectively explain their understanding of how and why the properties of multiplication can be used to write equivalent equations that help us solve multiplication problems.

**Key vocabulary:**

- addend
- area model
- column
- equation
- factor
- parentheses
- property
- rectangular array
- row
- strategy

**Special materials needed:**

- grid paper
- square tiles