Ratios A ratio is a comparison of two items that are measured using the same unit of measure. Examples: - Boys to Girls (unit of measure = people) - Hours of HW to Hours of TV - Potato Chips you eat to Potato Chips Mr. F. eats - Your turn to think of one… discuss at your table

Rates A rate is a comparison of two items that are measured using different units of measure. Examples: miles per hour dollars per pound cupcakes per student students per classroom Your turn to think of one… discuss at your table

Rates vs. Ratios Rates and ratios are like identical twins. They look exactly the same, they are solved the same exact way, but there is one major difference. The difference we care about is the unit of measure… Same Unit = Ratio Different Unit = Rate

Can you figure out which of the following is a rate? Which is a ratio? 1) Cards Up to Cards Down 2) Shots Made to Shots Missed 3) Miles per Hour 4) Calories per Serving 5) Students in Band to Students in 6 th Grade Can you find a “trick” to help you remember the difference between rates and ratios? Ratio Rate Ratio

This year the Green Bay Packers finished with a record of 14 wins and 6 loses. We can represent this information in a variety of ratios…

Part-to-Part: A ratio that compares parts of information. In this case the ratio would be games won to games lost. The ratio would be…

Part-to-Whole: A ratio that compares a part of the information to all of the information. In this case it would be games won to all of the games played. The ratio would be… You could also compare the games lost to all of the games played.

Using Ratio Language If you are told the ratio of students to teachers is 24:1, this would be expressed by saying, “For every 24 students there is one teacher.” It is important to read the ratio in the order that it is written. Since the 24 comes first, it represents the students. Since the 1 comes next, that means it represents the teachers. If we disregarded the order of the numbers in the ratio, the reader would not know if the 24 represented the students or if it represented the teacher(s). This could become very confusing!

Imagine that someone read the previous ratio incorrectly and thought, “There are 24 teachers for every 1 student.” How would a mistake like this impact a school?