You want to leave a 15% tip on a meal that cost $65.00.
First, convert the 15% to an actual number that can be used in a calculation. For percents,this is always done by simply dividing the percent (in this case 15%) by 100%.So, the conversational term "15%" becomes 15% / 100% = 0.15 in terms of a real mathematical number.
Second, you need to find out what 15% of your $65.00 meal cost is.This is always done by multiplying 0.15 by $65.00, or
0.15 x $65.00=$9.75.
So, the amount of tip you are going to leave is $9.75.
This makes the total cost of your meal (to write on your charge slip or other payment)
$65.00 + $9.75 = $74.75.