Frequently Asked Questions
Everything you need to know about Percentage
What is the basic formula for calculating percentages?
+ The fundamental percentage formula is: (Percentage value / Initial amount) = (The percentage / 100). This can be rearranged to solve for any missing value. For example, to find 30% of 120, you would calculate: X/120 = 30/100, then cross multiply to get X = 36.
How do I calculate a discount percentage on a sale price?
+ To find a discount: 1) Multiply the percentage by the original price, 2) Divide by 100 to get the discount amount, 3) Subtract from original price. For example, a 25% discount on $200: (25 × 200) ÷ 100 = $50 discount, so final price is $200 - $50 = $150.
What's the difference between finding a percentage OF something versus finding what percentage something IS?
+ Finding a percentage OF uses: (percentage/100) × total = result. Finding what percentage something IS uses: (part/whole) × 100 = percentage. For example: 20% of 50 = 10, but 10 is 20% of 50.
How do I solve percentage word problems step by step?
+ Follow these steps: 1) Identify what represents 100% (the whole), 2) Identify the percentage given, 3) Determine what you're solving for, 4) Set up the proportion using the formula, 5) Cross multiply and solve. Always ask yourself 'percentage of what?' to identify the whole.
Why do I get a number higher than the original when calculating percentage increases?
+ When something increases by a percentage, the result represents more than 100% of the original. For example, if a $50 item increases to $58, it's now at 116% of its original price (a 16% increase). Values above 100% indicate growth beyond the starting amount.
How do I convert fractions to percentages quickly?
+ Multiply the fraction by 100. For example: 3/5 × 100 = 300/5 = 60%. This works because percent means 'per hundred,' so you're finding how many parts per 100 the fraction represents.
What's the trick for calculating 10%, 25%, and 50% mentally?
+ Use these shortcuts: 10% = divide by 10, 25% = divide by 4, 50% = divide by 2. For other percentages, combine these: 30% = 10% × 3, 75% = 25% × 3. For example: 25% of 80 = 80 ÷ 4 = 20.
How do I check if my percentage calculation is correct?
+ Use reverse calculation: if 30% of 120 = 36, then 36/120 × 100 should equal 30%. Also, sense-check your answer: 50% should be half, 25% should be one-quarter, 10% should be one-tenth of your starting number.