Lesson objective: Students will be able to show the same amounts of money with different groups of coins.

Students bring prior knowledge of the values of dollars and coins and counting groups of money from 2.MD.C.8. This prior knowledge is extended to show the same amount of money as students use different combinations of coins and/or dollars. A conceptual challenge students may encounter is determining which different coins or dollars could be combined to create the same amount of money.

The concept is developed through work with physical coins or labeled drawings of the coins, which supports representing the same amount of money with two (or more) different groups of coins.

This work helps students deepen their understanding of equivalence because combining different dollars or coins can create the same total amount of money.

Students engage in Mathematical Practice 2 (Reason abstractly and quantitatively) as they determine which different groups of coins can be combined to create the same amount of money. Students need to have a solid understanding of the value of each coin, and how these coins can be combined in different ways to show the same amount of money.

**Key vocabulary:**

- amount
- equal
- group of coins
- value

**Special materials needed:**

- coins
- dollars
- hundreds grid
- number lines