An equation has been laid down using a few matchsticks. However, as you can see, the equation is not correct. Can you correct the equation if you are allowed to add or remove 5 matchsticks?

Solve below popular number sequence
314 159 265 358 979 323 846 ?

How can you leave a room with two legs and return with six legs?

Look at the below sequence of letters and tell us what the next letter should be:

O T T F F S S ?

There is a place where if I stand up straight, I will still be considered sideways.

Find the next number in the sequence

5 12 24 36 ?

Your last good ping-pong ball fell into a narrow metal pipe embedded one foot deep in concrete.
How can you get it out undamaged, if all the tools you have are your tennis paddle, shoe laces, and plastic water bottle, which does not fit into the pipe?

I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

The answer I give is yes, but what I mean is no. What was the question?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.