Your friend gave you a gift card for your birthday. You use it to buy a DVD for $15. The gift card balance shown on the receipt after the purchase is $45. What was the original value of the gift card?
The total amount of the gift card is the amount left on it plus anything that has been spent so far. So in your problem...
Total original value = 45 + 15 = $60
Another way to look at it would be that you started out with a certain amount of dollars (let's call it x) and subtracted 15 dollars and now you have 45...
x - 15 = 45
x = 45 + 15
x = $60
the value was $60 because u got to add that 45 to the 15 and that's the answer