A simple 3rd grade math problem

[Chiefnj2]

-$18.00 purchase of sweater.

$100 dollar bill directly to neighbor. He is still out $18.
Receives $100 singles back. Not his money yet.
Gives $79 singles away to the purchaser.
Keeps $21 singles.

Difference between purchase of sweater -$18 and $21 kept, is +$3.

Next day neighbor wants money back. He gives $100 to neighbor. That leaves him with -$97 and a bogus Franklin.