Can you solve this tricky maths equation problem by replacing it? mark with the correct symbol?

19834 -----: 187
15921 -----: 153
17561 -----: 139
13734 -----: ???

You can take four of the five letters out of this word, but the pronunciation never changes. What is the word?

John has eleven friends. He has a bowl containing eleven apples. Now He wants to divide the eleven apples among his friends, in such a way that an apple should remain in his bowl.
How can He do it?

Only one color, but not one size,
Stuck at the bottom, yet easily flies.
Present in sun, but not in rain,
Doing no harm, and feeling no pain.
What is it?

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

Which number comes next in the number series?

2, 9, 30, 93, ?

No one wants to have it, but if one got it, he does not want to lose it. What is It?

I am under you when I am whole.
I shift above you if you remove the first letter.
I come all around you if you remove the second as well.

Can you tell me who I am?

Which number should replace the question mark?

Which is the smallest number that you can write using all the vowels exactly once?