# 7.16: Smart Shopping

**Smart Shopping - Reason Proportionally Using Least Common Multiples**

**Teacher Notes**

Smart Shopping shows prices for the same item from two different stores. To determine the better buy, students equate the number of items in order to compare prices. To accomplish this, they 1) identify the least common multiple of number of items, 2) the prices for those numbers of items, and 3) and compare prices to determine the better buy.

**Solutions**

**Which store has the better buy for calendars?**

**What is the least common multiple of 3 and 4?**

**Which store has the better buy? How did you figure it out?**

**What is the least common multiple of 2 and 5?**

**Which store has the better buy? How did you figure it out?**

**What is the least common multiple of 5 and 3?**

**Which store has the better buy? How did you figure it out?**