Lesson objective: Solve problems involving multiplication and division to plan three possible menus for a school picnic.

This lesson provides an opportunity for students to apply their knowledge and understanding of the standard algorithm for multiplication and using arrays to solve division problems to a real-life situation. Students are asked to create three possible menus for a student picnic that will feed 120 students for $1,100 or less. They are also asked to determine the cost of each dessert (for each contributing group) if the total cost is to be split equally between the three groups.

Key Concept students will use:

- The standard algorithm for multiplication is an efficient way to multiply that uses place value concepts.
- We can relate the dividend, divisor, and quotient in a division problem to parts of an array model.

Skills students will use:

- Use of array models for multiplication; Grade 4 Unit 2; 4.NBT.B.5
- Decomposing numbers to find a product; Grade 4 Unit 2; 4.NBT.B.5
- Prior experience with division strategies; Grade 4 Unit 2; 4.NBT.B.6
- Division-related vocabulary: divisor, dividend, quotient; Grade 4 Unit 2; 4.NBT.B.5

Students engage in Mathematical Practice 1 (Make sense of problems and persevere in solving them) as they create three possible menus for a student picnic that will feed 120 students for $1,100 or less.

**Key vocabulary: **

- array
- divisor
- dividend
- quotient
- standard algorithm

**Special materials needed:**

- base ten blocks (optional)