Lesson objective: Compare decimals with different numbers of digits.

This lesson provides an opportunity for students to apply their knowledge and understanding of decimals to a real-life situation. Students are asked to determine the possible thicknesses of specific coins and compare these to another and to the depth of the coin slot on the vending machine.

Key Concept students will use:

- Decimals with different numbers of digits to the right of the decimal point can be compared

Skills students will use:

- Understand the place value system
- Read, write, and compare decimals to thousandths
- Compare numbers using >, =, and < symbols (4.NBT.A.2)

Students engage in Mathematical Practice 7 (Look for and make use of structure) as they compare decimals to decide possible thicknesses for each of the different coins.

**Key vocabulary: **

- compare
- decimal
- equal to
- greater than
- less than
- place value
- tenths
- hundredths
- thousandths

**Special materials needed:**

- scratch paper, as needed