100 likes | 368 Views
Ratios and Unit Rates. Today’s Objective. Use ratios and unit rates to model, describe and extend problems in context. Ratios. A ratio is a comparison of numbers that can be expressed as a fraction.
E N D
Today’s Objective • Use ratios and unit rates to model, describe and extend problems in context.
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
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.
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
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
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.
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
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
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