Introduction to Percent of Change

Percent of Change

The original amount is the starting value relative to when the change is being observed. This problem is observing the change in population from 1970 to 2017, so the population in 1970 is the original amount.

​

​Identify the Original Amount

The amount of change is the difference between the original amount and the current (or final observed) amount.

​

​Find the Amount of Change

Simplify the formula by carrying out the division represented by the fraction.

The result is the decimal form of the percent that you are looking for.

​

​Simplify

Convert from the decimal form to the percent form by multiplying by 100..

​

Convert Decimal Form to Percent Form

Since the population declined from 1970 to 2017, you would say that Pittsburgh's population decreased by 12.3% from 1970 to 2017

Identify Increase or Decrease

1970 = 2,683,970
2017 = 2,353,045

Multiple Choice

In 2016, the population of San Antonio, Texas was 1,487,738. In 2017, its population was 1,511,946.

Would the percent of change in San Antonio's population represent an increase or decrease in the population?

• Increase

• Decrease

• Stays the same

Multiple Choice

In 2016, the population of San Antonio, Texas was 1,487,738. In 2017, its population was 1,511,946.

What is the amount of change in San Antonio's population from 2016 to 2017?

1,511,946 - 1,487,738 = ?

• 24,208

• 2,999,684

Multiple Choice

In 2001, there were 128,374,512 active cell phones in the United States. By 2010, the number of cell phone users in the United States had become 300,520,098. What is the percent of change in cell phone users in the United States from 2001 to 2010?

• Increase by 134%

• Decrease by 13%

• Decrease by 134%

Multiple Choice

In 2015, your friend bought a comic book for $10.99. It is now worth $54.49.

What is the approximate percent of change in the value of your friend's comic book?

Round your answer to the nearest percent.

• 396% Increase

• 596% Increase

• 3960% Decrease

Multiple Choice

In 1990, there were 3,317 home runs hit in major league baseball. In 1991, major league baseball players hit 3,383 home runs.

What is the approximate percent of change in major league baseball home runs from 1990 to 1991?

Round your answer to the nearest hundredth of a percent.

• 19.9% Increase

• 199% Decrease

• 1.99% Increase

Multiple Choice

The purchase price of a given stock was $52.50 in 2015. Today, the same stock sells for $49.75.

What is the approximate percent of change in the stock price from 2015 to today?

Round your answer to the nearest hundredth of a percent.

• 5.24% increase

• 5.24% decrease