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

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

It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

I have one of the three numbers: 1, 2, or 3 in my mind. I speak only truth. You can ask me just one question for which I will only reply in yes or no or don't know. What question will you ask from me so that you are able to know the number?

Find the last number in the series below:

voN luJ yaM raM ---

My thunder comes before the lightning; my lightning comes before clouds; my rain dries all the land it touches. What am I?

Find three numbers such that When we multiply three numbers, we will get the prime numbers. The difference between the second and the first number is equal to the third and second.

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

Do you know of a place where the wind blows south and then suddenly shifts direction towards the north?

Can you name three consecutive days without using the words Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, or Sunday?

Why do Chinese men eat more rice than Japanese men do ?