Core percentage ideas
“Percent” means “per hundred.” Divide a percentage by 100 to write it as a decimal. Then multiply to find a part or divide to work backward to the whole.
Percentage Solver
Solve the three most common percentage problems and see the decimal conversion and arithmetic.
Choose the problem
ANSWER
—
Step-by-step work
Example: 20% of 150
Convert 20% to 0.20, then multiply: 0.20 × 150 = 30.
Common mistake
Percentage change always divides by the starting value, not the ending value. The starting value is the reference point for measuring the change.