Identify the total amount (whole).
Identify the part amount (portion).
Use: percentage = (part ÷ whole) × 100
If you have a decimal: multiply by 100
If you have a fraction: convert to a decimal, then multiply by 100
For “what percent is A of B”: percentage = (A ÷ B) × 100
For “A is what percent of B”: percentage = (A ÷ B) × 100
For “find the part from a percent”: part = (percentage ÷ 100) × whole
For “find the whole from a percent”: whole = part ÷ (percentage ÷ 100)
For “increase/decrease percent”: percentage change = ((new − old) ÷ old) × 100