Lesson objective: Multiply decimal numbers with factors greater than one.

This lesson helps to build procedural skill with multiplying decimal numbers. Rectangular arrays are used here because they support the importance of place value when multiplying decimal numbers. This work develops students' understanding that the relationship between factors and products remains the same with decimal numbers.

Students engage in Mathematical Practice 7 (Look for and make use of structure) as they make the connection between the size of factors and products and learn to multiply and then divide by powers of ten using the compensation method.

**Key vocabulary:**

- area model
- array
- compensate
- factor
- product
- reasonable
- relationship

**Special materials needed:**

- flats, rods, and cubes
- number lines
- squared paper