What is 15% of 80?

Percent of a number = (percent ÷ 100) × number. 15% of 80 = 0.15 × 80 = 12. Three methods to solve percent problems: (1) Convert percent to decimal and multiply: 15% = 0.15; 0.15 × 80 = 12. (2) Use the fraction equivalent: 15% = 15/100; (15/100) × 80 = 1200/100 = 12. (3) Set up proportion: 15/100 = x/80; cross-multiply: 100x = 1200; x = 12. Useful percent shortcuts to memorize: 10% = move decimal point one place left (10% of 80 = 8); 1% = move decimal two places left; 25% = ÷ 4; 50% = ÷ 2; 75% = (number × 3) ÷ 4. For 15%: take 10% (which is 8) and add half of that (4) = 12. Practice mental math with percentages — it saves time on the ASVAB.