1. Ratios and Unit Rates

2. Today’s Objective Use ratios and unit rates to model, describe and extend problems in context.

3. Ratios A ratio is a comparison of numbers that can be expressed as a fraction. If there were 10 boys and 12 girls in a class, you could compare the number of boys to girls by saying there is a ratio of 10 boys to 12 girls. You could represent that comparison in three different ways: – 10 to 12 – 10:12 – 10 12

4. Practice A basketball team loses 6 games and wins 9 games. Find the ratio of: Losses to wins – 6 to 9 = 6:9 = 6/9 Wins to losses – 9 to 6 = 9:6 = 9/6 The order of the numbers are very important.

5. Practice A bag contains 12 white, 9 red and 1 5 blue balls. What is the ratio of the following? – White balls to blue balls? 12 to 15 = 12:15 = 12/15 – Blue balls to red balls? 15 to 9 = 15:9 = 15/9 – Red balls to white balls? 9 to 12 = 9:12 = 9/12

6. Rates A rate is a ratio that compares two numbers measured in different units. Rates are often written in fraction form. Ex: Sam can type 30 words in 2 minutes. Ratio: 30 words 2 minutes

7. Unit Rate Most of the time when we work with rates we use a unit rate. A unit rate compares a number to one unit of another number.

8. Unit Rate Ex: Sam can type 30 words in 2 minutes. How many words can he type in 1 minute? Ratio- 30 words 2minutes Unite rate-30 words ÷ 2 = 15 words 2 minutes ÷ 2 1 minute

9. Practice There are 60 students to 3 buses. How many students are there in one bus? Ratio - 60 students 3 buses Unit rate - 60 students ÷ 3 = 20 students 3 buses ÷ 3 = 1 bus

10. Practice There 20 soccer players to 5 soccer balls. How many soccer players are there to one soccer ball? Ratio- 20 players 5 balls Unit rate- 20 players ÷ 5 = 4 players 5 balls ÷ 5 = 1 ball