Examples: 12 out of 20, 12 boys and 8 girls Ratios and Rates What are some ways you can compare the number of boys to total students in this classroom? Examples: 12 out of 20, 12 boys and 8 girls

A ratio is a mathematical way to compare two quantities …you can compare part to part In our example boys to girls …you can compare part to whole In our example boys to total …you can compare whole to part In our example total to girls

12 to 20 A ratio can be written in 3 ways: A ratio can be written in simplest form just like a fraction

A rate is a comparison of two quantities using different units examples: A unit rate is a rate where the denominator is one unit examples:

How do you change a rate into a unit rate? look at our previous example: One method  Divide the numerator by the denominator Which is the same as Dividing both the numerator and denominator by 4

Let’s practice on whiteboards

Try changing these to unit rates Typing 300 words in 6 minutes Running 15 km in 45 minutes Solving 20 math problems in 30 minutes

Let’s see what happens to these “units” when solving a problem Luke texts 25 words/minute. How many words can he text in 30 minutes?

Pete drives at a speed of 50 kilometers per hour Pete drives at a speed of 50 kilometers per hour. How far will he go in 4 1/2 hours? Katie counted 24 petals on one of the dozen roses that her boyfriend gave her. About how many petals would there be on all the roses together?

Using unit rates is a good way to compare… Which is the better price? $6.25 for 25 oranges or $7.20 for 30 oranges?

You can find unit rates in different ways… In a table From a graph From an equation M = 55G