Can you fill the blank with the correct number?

6 30 870 756030 _____

My cousin lives in one story house in Antarctica. His house is made the of-of sandstone. what is the color of stairs?

One day, I thought of ways that can be used for creating a palindrome. So I decided that I will turn into a larger number by adding the reversed digits to the original number and keep doing it till I finally obtained a palindrome.

I am not sure if this process will always result in a palindrome eventually but I was able to produce a four-digit palindrome. Can you guess my starting number?

Solve the mathematical equation in the picture below.

You are in a land where thirty men and two women were dressed in classic black and white dresses.
They begin to fight as soon as any of them move.

Where are you?

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?

What does a man do only once in his lifetime, but women do once a year after they are 29?

If I put in one bird per cage, I have one bird too many. If I put in two bird per cage, I have one cage too many. How many cages and birds do I have?

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

I got a bee but no honey.
got an eye but am still blind.
got a sea but no water.
got a tea but no coffee.
got a why but no answer.

What Am I?