Take away my first letter, then take away my second letter. Then take away the rest of my letters, yet I remain the same. What am I?

Here is a mathematical expression that also secretly tells a movie name. What movie is that?

What has many keys but can’t open a single lock?

How many letters are in the alphabet?

I noticed one of the words in the oxford dictionary is spelled incorrectly. What about you?

I have one of the three numbers: 1, 2, or 3 in my mind. I speak only truth. You can ask me just one question for which I will only reply in yes or no or don't know. What question will you ask from me so that you are able to know the number?

Can you spot the hidden girl in the picture below?

You enter your friend's room. He is not in his room. Although you see that on the bed there are two dogs, five cats, two giraffes and three pigs. Also, a couple of chickens and ducks are flying in the room.

Calculate the number of legs standing on the floor.

If you go to the movies and you're paying, is it cheaper to take one friend to the movies twice, or two friends to the movies at the same time?

It's a test that will check your IQ.

Suppose you have one 11 minute hourglass and one 13 minute hourglass.

Can you measure exactly fifteen minutes using them ?