Basic Percent Formulas Percent Increase
Basic Percent Formula
P
A

100 B
&
Percent Decrease
Step 1: Subtract
Step 2: Use Formula
How to find the Base?
The Base usually comes directly after the word “of”
The Base is usually the “Total Number”
The Base is often, but not always, the larger number.
How to find the Amount:
The Amount usually comes after the word “is”
The Amount is a “part” of the total number.
The Amount is often, but not always the smaller number.
p
Increase

100 Original Number
p
Decrease

100 Original Number
Converting
Basic Interest Formula
I = Prt
Interest = Interest in dollars. Principle = The amount invested. Rate = The interest rate; usually as a percent. Time = The amount of time in years. How to determine time when less than one year: Days ‐ Write over 365 Months ‐ Less than or more than a year, write over the number of months. Saved: EPCC (Math Emporium) HANDOUT Percent Formulas
Fraction to Decimal
Decimal to Fraction
Decimal to Percent
Percent to Decimal
Divide Write over place value and reduce Move decimal point two places to the Right Move decimal point two places to the Left.