## Percent Change

## Formative Assessment

# Summary of the Math: Percent Change

**Read and Discuss**

- A percent can describe a change in a value—for example, a percent increase.
- If a value increases by
*x*%, you can calculate the new value in two ways:- Calculate
*x*% of the original amount and add the result to the original amount. - Calculate (100% +
*x*%) of the original amount.

- Calculate
- For example, if the percent increase is 5% and the original amount is m, then:

0.05 +*m*= the total amount, or 1.05*m*= the total amount - These two equations are equivalent because:

0.05*m*+*m*= 1.05*m*

0.05*m*+ 1*m*= 1.05*m*(0.05 + 1)*m*= 1.05*m*

## Hint:

Can you:

- For a problem about a sales tax situation, create a table that can help you organize what is given and what you need to find?
- Use a table to make a graph?
- Determine one of the amounts in a sales tax situation—the price of an item, the amount of the sales tax, or the total cost—if you know the other two amounts?