What is both possible and impossible at the same time?

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

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

You are playing a game with your friend Jack. There are digits from 1 to 9. You both will take turn erasing one digit and adding it to your score. The first one to score 15 points will win the game.

Would you want to play first or second?

PS: The sum should be exactly 15.

I have four wings but can't fly.
I express no emotions.
I am found on the exact spot every time you look.
I keep toiling away with a little sound.

Do you know what am I?

How many times can you subtract the number 5 from 25?

Can you make four (4) nines (9) equal 100?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

The more you take me, the more you leave me behind.
Who Am I?

What has many keys but can’t open a single lock?