There came a customer to a hat shop and chose a hat for 75 euro. He gave the saleswoman a one hundred pounds banknote. The saleswoman had no change money (so did the customer) so she ran off to the neighbouring hairdresser's to change the "hundred". After a while, she came back, made change and the satisfied customer left the shop.
Not a minute passed when the hairdresser barged in having a claim that the bill, which she had handed him, was false and therefore she should give him 100 euro. The banknote turned out to be indeed false. The scammed saleswoman sat depressed and started counting how much she had lost because of that customer's dishonesty; not only did she give him the hat, but she made change, and now she had to give the hairdresser's back his 100 euro. She was counting, and counting, but no matter how hard she tried, she couldn't end up with an equal sum.
So there is a question: how much did she loose?