The term percent comes from Latin and means "for every hundred". So when you hear a statistic such as "10% of all people are left-handed" that means, for every hundred people, 10 are left-handed.

Percent of change (percent of increase or percent of decrease) can be calculated using the following formula:

**Example:** Richard's health insurance premium for last year was $1440. If he paid $1512 this year, what is the percent of increase on his health insurance premium?

Answer:($1512-$1440)/$1440 — 100% = 72/1440 — 100% = 5% Hence, the percent of increase on the health insurance premium is 5%.

Example: A T-shirt is sold at 20% off the original price of $32. What is the sales price?

Answer: Let the sales price be x dollars. ($32-x)/$32 — 100% = 20% ($32-x)/$32 = 0.2 $32 - x = $6.4 x = $25.6 Hence, the sales price of the T-shirt is $25.6.