What is 30% of 80?

Percent means 'per hundred'; convert to a decimal or fraction and multiply. 30% = 0.30 = 30/100 = 3/10. So 30% of 80 = 0.30 × 80 = 24. Or use fraction: (3/10) × 80 = 240/10 = 24. Percent applications: (1) Tax: total = price × (1 + tax rate); (2) Discount: sale price = original × (1 − discount rate); (3) Tip: tip = bill × tip rate; (4) Percent change: (new − old)/old × 100%; (5) Percent of: percent × whole. Useful percent equivalents to memorize: 10% = 0.10 = 1/10; 20% = 0.20 = 1/5; 25% = 0.25 = 1/4; 33⅓% = 1/3; 50% = 0.5 = 1/2; 66⅔% = 2/3; 75% = 0.75 = 3/4. Quick mental math: 10% of any number is the number with the decimal moved one place left; for 30%, take 10% and multiply by 3. Percent increase: if price rises 20%, multiply by 1.20; if it rises 50%, multiply by 1.50. Percent decrease: multiply by (1 − percentage).