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# 7th Grade Math / Lesson 1: Percents

 PERCENTS What will we be learning in this lesson? In this lesson, you will learn how to evaluate percents. Vocabulary words are found in this purple color throughout the lesson. Remember to put these in your notebook.

 PERCENTS Percents are used to help make comparisons. They compare quantities in terms of 100. The word "percent" actually means "per hundred". There is a proportion to use when solving any type of percent problem. Suppose you want to know what the percent is that you would pay for a shirt at a clothing sale. Say the original price of a shirt was  \$25 but you only paid  \$20. The "whole" would be the  \$25 (original price of the shirt) and the "part" would be the  \$20 (what you paid). Let's look at how to solve this.

 PERCENTS First, put the numbers in where they belong. Then, solve the proportion. Find the numbers on the diagonal that you know. There are two diagonals - the 20 and the 100 is one of them, and the % and the 25 is the other diagonal. We will need to use the diagonal with the 20 and the 100 since we know both of the numbers. MULTIPLY these numbers together. 20 * 100 = 2000 Now take that answer and DIVIDE by the other number in the problem that has not been used yet. 2000 � 25 = 80.So the percent of the price that you will pay is 80% of the original price.

 PERCENTS Let's find another one. There are 30 students on the class roster. There are 27 students in attendance today. Find the percent of students that are here. You need to figure out what you know and what you are looking for. The problem says to "Find the percent..." so the percent is the number we are looking for. So the other numbers are the "part" and the "whole" in the proportion. Which one is which? Is 30 the "part"? Or is it the "whole"? Since this is the total number of students in the class, it is the "whole" which leaves 27 as the "part". PERCENTS Now let's solve the proportion. Find the diagonal of numbers that we know. Multiply the numbers on this diagonal. 27 * 100 = 2700 Then divide by the other number that you haven't used yet.2700 � 30 = 90 So the percent of students who are in class today is 90%

 PERCENTS REMEMBER Once you have your proportion set up, MULTIPLY the diagonal of numbers that you have, then DIVIDE by the number not used yet. Can you set up the proportion to find a percent? Can you solve the proportion to find a percent? Be sure to go back to your classroom to get any homework assignments or other activities you need to attend to.