You saw a shirt for $97.
You didn’t have the cash, so you borrowed $50 from mom and $50 from dad.
50 + 50 = 100
You bought the shirt and had $3 change.
You gave your mom $1 and your dad $1 and kept the other $1 for yourself.
Now you owe your mom $49 and your dad $49.
49 + 49 = 98 + your 1 = 99
Where is the missing $1?