Three men go to a restaurant. They order some food. After they have finished, they ask for the bill. The bill was 30$ . They pay the bill and leave the restaurant.

As soon as they leave, the manager find out that there was a miscalculation and that they actually had to pay 25$ .

He calls the waiter, give him the extra 5\$, and ask him to pass this money back to men. The waiter leaves the restaurant with 5\$ , but he pot 2% in his pocket and give each man 1$.

So

Each man payed $ 10\\\$-1\\\$ = 9\\\$ $.
Three man payed $ 9\\\$*3=27\\\$ $.
The waiter has $ 2\\\$ $
The total is $ 27\\\$ + 2\\\$ = 29\\\$ $

Where is the last $ 1\\\$ $?