Lesson objective: Understanding place value allows us to multiply more efficiently using base ten blocks and arrays.

Students bring prior knowledge of multiplication arrays from 3.OA.A.1. This prior knowledge is extended to place value in arrays as students solve one- and two-digit multiplication problems. A conceptual challenge students may encounter is decomposing place value and base ten block representation.

The concept is developed through work with base ten blocks and arrays, which gives concrete connections to place values.

This work helps students deepen their understanding of operations because multiplication problems can be solved using place value decomposition and the distributive property.

Students engage in Mathematical Practice 7 (Look for and make sure of structure) as they compare and contrast two different types of arrays and the use of decomposition and place value in each.

**Key vocabulary:**

- array
- base ten block
- cube
- decomposition
- flat
- place value
- rod

**Special materials needed:**