# Percent Increase and Decrease

Video solutions to help Grade 7 students learn how to solve percent problems involving a percent increase or decrease.

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Lessons for Grade 7
Common Core For Grade 7
## New York State Common Core Math Grade 7, Module 4, Lesson 4

### Lesson 4 Student Outcomes

• Students solve percent problems when one quantity is a certain percent more or less than another.

• Students solve percent problems involving a percent increase or decrease.

Lesson 3 Classwork
Opening Exercise

Cassandra likes jewelry. She has five rings in her jewelry box.

a. Draw a double number line diagram relating the number of rings as a percent of the whole set of rings.

c. What percent is represented by the whole collection of rings? What percent of the collection does each ring
represent?

Example 1

Cassandra’s aunt said she will buy Cassandra another ring for her birthday.

If Cassandra gets the ring for her birthday, what will be the percent increase in her ring collection?

Example 2: Percent Decrease

Ken said that he is going to reduce the number of calories that he eats during the day. Ken’s trainer asked him to start off
small and reduce the number of calories by no more than 7%. Ken estimated and consumed 2,200 calories per day
instead of his normal 2,500 calories per day until his next visit with the trainer. Did Ken reduce his calorie intake by 7%?
Justify your answer.

Example 3: Finding a Percent Increase or Decrease

Justin earned 8 badges in Scouts as of the Scout Master’s last report. Justin wants to complete 2 more badges so that he
will have a total of 10 badges earned before the Scout Master’s next report.

a. If Justin completes the additional badges, what will be the percent increase in badges?

b. Express the 10 badges as a percent of the 8 badges.

c. Does 100% plus your answer in part (a) equal your answer in part (b)? Why or why not?

Example 4: Finding the Original Amount given a Percent Increase or Decrease

The population of cats in a rural neighborhood has declined in the past year by roughly 30%. Residents hypothesize that
this is due to wild coyotes preying on the cats. The current cat population in the neighborhood is estimated to be 12.
Approximately how many cats were there originally?

Example 5

Lu's math level on her achievement test in 7th grade was a level 650. Her math teacher told her that her test level went
up by 25% from her 6th-grade test score level. What was Lu's test score level in 6th grade?