Teaching Percent of Number
When teaching students to find the percent of a number (or the part or whole), I introduce two different ways to find the missing number  using proportions and using equations. Since different students often prefer different methods, I teach both, have them practice both, and then let them choose the one they like better. I've given an example of each method below.
The Percent of a Number Wheel shown here includes both methods. Each section of the wheel includes an equation and two examples, with room to solve using both methods. There's also a little room on the wheel (or around it) to add extra notes or your own examples, if you'd like. Around the wheel are a few practice problems that can be completed together or individually.
Method 1: Proportion
1) Substitute the given values into the %/100 = IS/OF proportion. Use a variable for the missing number. 2) Solve the proportion to find the missing value. Example: What is 15% of 70?
Method 2: Equation
1) When given the percent, change it to a decimal. 2) Substitute the given values into the equation. Use a variable for the missing number. 3) Solve the equation. * If finding the percent, be sure the answer is in percent form (multiply the decimal answer by 100). Example: What is 15% of 70? part = % ∙ whole x = 0.15 ∙ 70 x = 10.5 When we work with the equations, I do manipulate the equations to show students how they are all versions of the same basic equation. For example, if we start with part = % ∙ whole and we're looking for the whole (say the part is 35 and the percent is 25), we end up with 35 = 0.25 ∙ x. From solving algebraic equations, students know that to find x, both sides will be divided by 0.25, which gives them x = 35/0.25 (whole = part/%) If you decide to use the wheel, I hope you and your students like it!
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AuthorHi, I'm Ellie! I've been in education for 25 years, teaching all subject areas at both the elementary and middle school levels. Categories
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