If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

How many letters are in the alphabet?

I don't get anymore wetter, no matter how much rain falls on me.

How many sides does a circle have?

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

John’s parents have three sons: Snap, Crackle, and what’s the name of the third son?

O_er_t_o_

Complete the missing letters of the given word.

A man calls his dog from the opposite side of a river. The dog crosses the river without a bridge or a boat and manages to not get wet. How is this possible?

Can you solve this picture maths equation?

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?