Lesson 1: Ratios Warm-Up: 30 + 30 300 + 300 80 + 40 800 + 400 20 + 30 + 40 200 + 300 + 400 How many inches are in a foot? How many millimeters are in a centimeter?

Student Outcomes/Objectives: Students will understand a ratio is an ordered pair of numbers which are not both zero. Students will correctly read and write ratios. Students will understand that the order of the ratio matters and is determined by the description. Standards: 6.RP.A.1, 6.RP.A.2, 6.RP.A.3

What is a ratio? A ratio is a way to describe a relationship between numbers. If there are 13 boys and 15 girls in a classroom, then the ratio of boys to girls is 13 to 15 and the ratio of girls to boys is 15 to 13. (No labels needed) Ratios can be written in several forms. Each of these forms is a way to write the boy-girl ratio: 13 to 15 13:15 13/15 Each of these reads “thirteen to fifteen.”

How do we write ratios correctly? 1.We write the terms of the ratio in the order we are asked to give them. 2.We reduce ratios in the same manner as we reduce fractions. 3.We leave ratios in fraction form. We do not write ratios as mixed numbers and we do not label.

Example: The coed soccer team has four times as many boys on it as it has girls. We say that the ratio of the number of boys to girls on the team is 4:1. We read this as four to one. Let’s make a table (or ratio box): Boys 4 8 ? Girls 1 3 Total

Example: Suppose the ratio of the number of boys to girls on the team is 2:3. Fill in the ratio box to show this is true. Visualize: Girls: Boys:

Student Examples: Write a ratio for the following description: Kaleel made three times as many baskets as John during basketball practice. Describe a situation that could be modeled with the ratio 4:1. Write a ratio for the following description: For every 6 cups of flour in a bread recipe, there are 2 cups of milk.

Student Examples: A team lost 3 games and won 7 games. What was the team’s win-loss ratio? What is the the team’s loss-win ratio? In a class of 28 students, there are 13 boys. What is the ratio of boys to girls in the class?

Addition and Subtraction Review: 345 + 67 $1.25 + $12.50 + $5 345 – 67 = Jim spent $1.25 for a hamburger. He paid for it with a five-dollar bill. Find how much change he should get back by subtracting $1.25 from $5.

Assignment: Module 1, Lesson 1 worksheet due tomorrow!