There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

Twenty frogs are sitting on a log floating on the surface of a river. Two of them decide to jump off into the water.

How many frogs are there on the log at this moment?

A man started to town with a fox, a goose, and a sack of corn. He came to a stream which he had to cross in a tiny boat. He could only take one across at a time. He could not leave the fox alone with the goose or the goose alone with the corn. How did he get them all safely over the stream?

If eleven plus two equals one, what does nine plus five equal?

There are five vowels (a, e, i, o, u) in the English language.
Can you tell us a word that contains all these vowels?

How many times can you subtract the number 5 from 25?

Pronounced as one letter,
And written with three,
Two letters there are,
And two only in me.
I am double, I am single,
I am black blue and grey,
I am read from both ends,
And the same either way.

Fate has decided that you will only be pleased to meet me when you need me

Maybe that is why, when I am working, I start working

However annoying I may be to the regulars, the little ones are always inspired

I will always be waiting if you try to reach me

How many of you can guess my name, let me see

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?