You need to move three matchsticks to form three squares. Can you do it?

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

A number can be multiplied by multiple of nine
i.e 9 18 27 36 45 ...

and the resulting number consist of only one digit.

Can you identify the number ?

The following sentence is false. The preceding sentence is true.
Are these two sentences true or false?

Which tank will fill first?

What work can one never finish?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

A mules travels the same distance daily.
I noticed that two of his legs travels 10km and the remaining two travels 12km.
Obviously two mules legs cannot be a 2km ahead of the other 2.

The mules is perfectly normal. So how come this be true ?

What four weights can be used to balance from 1 to 30 pounds?

A boy purchased a book from a bookkeeper and gave him $100.
The cost of the book is $50 but the bookkeeper has no change, so he gets the change from the next shop and returns the boy his $50.

After some time the next shopkeeper came with the $100 note and told the bookkeeper that the note was a fraud, so he took the money back.

How much loss did the bookkeeper face?