A math riddle!

Here is a riddle challenge for you:

You see an mp3 player at the store that costs 97 dollars.

You don't have the money so your dad gives you a 50 dollar bill and your mom gives you another 50.

You buy the mp3 player and the clerk gives you back 3 dollars.

You give back your dad 1 dollar, then you give back your mom 1 dollar and you keep the other dollar.

You owe your dad 49 dollars, and your mom 49 dollars.

49 + 49 = 98 dollars, plus the dollar you kept as change is 99 dollars, that is 49 + 49 + 1 = 99 dollars

If they lent you 100 dollars, what happened to the missing dollar???