Lesson objective: Apply properties of multiplication to solve problems.
This lesson provides an opportunity for students to apply their knowledge and understanding of the associative and distributive properties of multiplication to a reallife situation. Students are asked to find ways to use a calculator to solve multiplication problems when specific number and operation keys on the calculator are broken. To solve the problems, students must create equivalent equations by decomposing numbers into simpler factors and addends and using the properties to multiply correctly.
Key Concept students will use:

the properties of multiplication and the relationship between multiplication and division to solve equations with an unknown
Skills students will use:
 decomposing numbers into simpler factors and addends
 applying the associative and distributive properties of multiplication
Students engage in Mathematical Practice 6 (attend to precision) as they decompose numbers and apply the properties of multiplication to rewrite equations in order to use the broken calculator.
Key vocabulary:
 addend
 factor
 parentheses
 product
 property
Special materials needed (optional):
 grid paper
 square tiles