I saw a shirt for $97. I borrowed $50 from my mom and $50 from my dad. I bought the shirt with $3 of change. I gave $1 to mom, $1 to dad, and kept $1 for myself. Now I owe my mom $49 and my dad $49. $49+$49=$98+my $1=$99. Where did the other $1 go?
Helpful Hint #1!
You already gave mom and dad back $1 each, therefore now you have $98 to spend...