Can you find out which number multiplied by itself will give the output as 12345678987654321?

Which number should replace the question mark?

I know a 5-digit number having a property that With a 1 after it, it is three times as large as it would be with a one before it.

Guess the number?

Cristina was born in 1888. She just had her 30th birthday today how did that happen?

I inserted a coin in a bottle and closed its mouth with the help of a cork. Now, I was able to take the coin out from the bottle without taking out the cork or breaking the bottle. Can you tell me how I did it?

There's one "sport" in which neither the spectators nor the participants know the score or the leader until the contest ends.

What is it?

Can you count the number of matches in the picture below ?

Make eight squares by moving only two matchsticks.
Note- Square can be of different sizes.

Spot what is wrong here in below Picture?

What 8 letter word can have a letter taken away and it still makes a word. Take another letter away and it still makes a word. Keep on doing that until you have one letter left. What is the word?