If you borrow $50 from your mom and $50 from your dad it makes $100. So the shirt you buy is $97. Then you have $3 left. So you keep $1 and you give $1 to your mom and $1 to your dad. So now u owe them $49 each. $49 plus $49 is $98 plus then $1 you have it is $99. So where is the other $1.