Find the next number in the sequence

1, 2, 6, 21, 88, __?

Can you find out which options fits best with the missing column?

Can you solve this picture maths equation?

You are given four tennis balls and asked to arrange those balls in a manner that the distance between each one of them is exactly equal. How will you do it?

How is the moon similar to a dollar?

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?

A four-digit number (not beginning with 0) can be represented by ABCD. There is one number such that ABCD=A^B*C^D, where A^B means A raised to the B power. Can you find it?

An inspection by the superintendent of St. Joseph School was scheduled on the next day. The class teacher Jenifer knew that he would be asking questions from her class and she would have to choose a pupil to answer. To offer a perfect impression over him, the teacher explained certain instructions to the students to maximise the chances of getting correct answer every time.

What did she say to the students?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

What can you hold in your right hand, but never in your left hand?