Lesson objective: Understand that the standard algorithm can be an efficient way to multiply that uses the distributive property and place value concepts.

Students bring prior knowledge of the area model and partial products strategies from 4.NBT.B.5. This prior knowledge is extended to connect these strategies to the standard algorithm as students link the role of place value and the distributive property in the standard algorithm. A conceptual challenge students may encounter is forgetting digit values when using the standard algorithm.

The concept is developed through work with the partial products strategy, which is condensed and reflected in the standard algorithm, thus solidifying the understanding that digit values must be considered when using the standard algorithm.

This work helps students deepen their understanding of the standard algorithm by reinforcing the role of place value and the distributive property. Students will not see the algorithm as a series of steps, but rather as an efficient way to multiply multi-digit numbers.

Students engage in Mathematical Practice 8 (Look for and express regularity in repeated reasoning) as they perform multiplication using the standard algorithm by connecting previous multiplication strategies (which explicity show the reliance upon place value and the distributive property) to the standard algorithm.

**Key vocabulary:**

- algorithm
- digit value
- distributive property
- multiplication
- partial products
- place value
- product
- standard algorithm