very nice trick, thanks for sharing. here is a question from me. three friends visited a hotel daily for break fast. three of them ordered same break fast. it cost them 10 dollar each.this time When they payed there bill the hotel manager gave them 5 dollar discount. he told the waiter to give them back 5 dollar. Now the waiter find it difficult to divide this 5 dollar in three part. so he gave each of them 1 dollar and kept 2 dollar. This means each friend payed 9 dollar for break fast. 9 multiplied by 3 friends equals to 27 + 2 dollar the waiter kept will give us 29 dollar total. tell me where the 1 dollar went