O_er_t_o_

Complete the missing letters of the given word.

How many letters are in the alphabet?

Can you find out the remainder when 3^300 is divided by 5?

What does this mathematical rebus means ?

A man lives on the fifteenth floor of an apartment building. Every morning he takes the elevator down to the lobby and leaves the building. In the evening, he gets into the elevator, and, if there is someone else in the elevator, or if it was raining that day, he goes back to his floor directly. Otherwise, he goes to the tenth floor and walks up five flights of stairs to his apartment. Can you explain why he does this?

It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

Can you find out the next digit in the following series ?

0, 0, 1, 3, 2, 6, 3, 9, 4, 12, 5, ?

What word begins and ends with an E, but has only one letter?

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

By moving exactly three matchsticks can you make the below equation true.It can be solved by 3 ways.