2, 3, 5, 9, 17, _ What is the next number in the sequence?

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

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?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

Use the digits from 1 up to 9 and make 100.

Follow the rules.
=> Each digit should be used only once.
=> You can only use addition.
=> For making a number, two single digits can be combined (for example, 4 and 2 can be combined to form 42 or 24)
=> A fraction can also be made by combining the two single digits (for example, 4 and 2 can be combined to form 4/2 or 2/4)

Question: how can we do this?

There is an English word that can be used up to four times in a row without modifying the spelling and form a valid grammatical sentence.

Do you know what word is that?

The following question it puts forth you:

25 - 55 + (85 + 65) = ?

Then, you are told that even though you might think it's wrong, the correct answer is actually 5!

Whats your reaction to it? How can this be true?

You bought me for dinner but never eat me. What am I?

Can you make a six-letter word using the letters N, A and B ?