I saw a shirt for $97. I borrowed $50 from mom and $50 from 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?
I borrowed $50 from mum and $50 from dad to buy a bag costing $97. After the purchase, I had $3 left. I returned $1 to dad and $1 to mum, and reserved $1 for myself. I now owe $49+$49=$98 plus the $1 I reserved for myself, which is $99. Where is the missing $1?