 # Part of a Whole as Percent

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Examples, videos, and solutions to help Grade 7 students understand that the whole is 100% and use the formula Part = Percent x Whole to problem-solve when given two terms out of three from the part, whole, and percent.

### New York State Common Core Math Grade 7, Module 4, Lesson 2

Download worksheets for Grade 7, Module 4, Lesson 2

### Lesson 2 Student Outcomes

• Students understand that the whole is 100% and use the formula Part = Percent x Whole to problem-solve when given two terms out of three from the part, whole, and percent.
• Students solve word problems involving percent using expressions, equations, and numeric and visual models.

Lesson 2 Summary

• Visual models or numeric methods can be used to solve percent problems.
• Equations can be used to solve percent problems using the basic equation:
Part = Percent x Whole

Lesson 2 Classwork

Opening Exercise
a. What is the whole unit in each scenario?
b. Read each problem and complete the table to record what you know.

Example 1: Visual Approaches to Finding a Part, Given a Percent of the Whole
In Ty’s math class, 12% of students earned an A on a test. If there were 30 students in the class, how many got an A?

Exercise 1
In Ty’s art class, 12% of the Flag Day art projects received a perfect score. There were 25 art projects turned in by Ty’s class. How many of the art projects earned a perfect score? (Identify the whole.)

Exercise 2
A bag of candy contains 300 pieces of 28% which are red. How many pieces are NOT red?
a. Write an equation to represent the number of pieces that are not red, n.
b. Use your equation to find the number of pieces of candy that are not red.
c. Jah-Lil told his math teacher that he could use the answer from part (b) and mental math to find the number of pieces of candy that are not red. Explain what Jah-Lil meant by that.

Lesson 2 Classwork

Example 2: A Numeric Approach to Finding a Part, Given a Percent of the Whole
In Ty's English class, 70% of the students completed an essay by the due date. There are 30 students in Ty’s English class. How many completed the essay by the due date?

Example 3: An Algebraic Approach to Finding a Part, Given a Percent of the Whole
A bag of candy contains pieces of which are red. How many pieces are red?
Which quantity represents the whole?
Which of the terms in the percent equation is unknown? Define a letter (variable) to represent the unknown quantity.
Write an expression using the percent and the whole to represent the number of pieces of red candy.
Write and solve an equation to find the unknown quantity.

Example 4: Comparing Part of a Whole to the Whole with the Percent Formula
Zoey inflated 24 balloons for decorations at the middle school dance. If Zoey inflated 15% of the balloons that are inflated for the dance, how many balloons are there in total? Solve the problem using the percent formula, and verify your answer using a visual model.

Example 5
Haley is making admission tickets to the middle school dance. So far she has made 112 tickets, and her plan is to make 320 tickets. What percent of the admission tickets has Haley produced so far? Solve the problem using the percent formula, and verify your answer using a visual model.

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