1. Objective: Learn: “ What is a ratio?” Learn to compare quantities using division.

2. A Ratio compares two quantities There are 3 ways to write a ratio- as a fraction, with a colon (: ), and with the word “to”. If we compare the numbers of boys to girls we write them as follows: 13 13:8 13 to 8 8 This means that there are 13 boys and 8 girls. You read all ratios as “13 to 8”. Example: In a group of 6 th graders, 16 were right-handed and 5 were left-handed. Find the ratio of right-handers to left-handers? Answer: right-handed = 16 16:5 16 to 5 left-handed 5 “The ratio of right-handed to left-handed is 16 to 5.”

3. Ratios can be written in Simplest Form. If the Ratios of cats to dogs is 16 to 14, you can divide both of the numbers by a common factor to make them smaller. For example: 16 cats to 14 dogs = 16 to 14 16:14 16 14 (if I divide them by 2)= 8 cats to 7 dogs= 8 to 7 8:7 8 7 Your Example: Write each ratio three ways. Write in simplest form if possible. 36 shoes to 27 socks = 10 tennis to 15 golf =

4. Homework: Write the ratios all three ways. Re-write in simplest form if possible. 1. 3 desktops to 8 laptops. 2. 8 Samsung to 14 I-phones. 3. 25 oranges to 45 apples. 4. 21 boys to 24 girls. 5. 4 wins to 6 losses. 6. 8 dentists to 10 pediatricians. 7. 36 balls to 48 bats. 8. 50 Barca to 35 Real Madrid. 9. 4 fish to 10 turtles. 10. 8 exams to 2 projects.