Matching Pairs Percent ReviewOnline version vocabulary and formulas for test review by STEPHANIE GREGORY 1 how to find percent error 2 how to find percent increase or percent decrease 3 To find the total after a disccount 4 interest 5 To change a decimal to a percent 6 To find the total after tax or gratuity 7 Principal 8 interest rate 9 To change a percent to a decimal 10 simple interest formula 11 how to find the percent of a number Multiply the cost by the percent as a decimal, then add it back to cost difference/original = %/100 the % being charged for a loan or the % being earned for investing the amount of money being invested or the amount of money being borrowed difference/actual = %/100 Move the decimal two times to the left is/of = %/100 the amount of money being charged to borrow money or the amount of money earned for investing money Multiply the cost by the percent as a decimal, the subtract that amount from the cost Move the decimal 2 times to the right I = PRT