Identify the hidden meaning behind this picture?

There is one four-digit whole number n, such that the last four digits of n2 are the original number n

I am not alive, but I grow; I don't have lungs, but I need air; I don't have a mouth, but water kills me. What am I?

It's a 7-letter word.
If we remove 1 letter from it, it remains the same.
If we remove 2 letters from it, it remains the same.
If we remove 3 letters from it, it remains the same.
If we remove all the letters from it, still it remains the same.
What is it?

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

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

The centre of the third figure is empty. What digit should fit inside?

I am the beginning of the end, and the end of time and space. I am essential to creation, and I surround every place. What am I?

What English word has three consecutive double letters?

When can we add 2 to 11 and get 1 as the correct answer?

Count The number of F's in the paragraph below:

"FINISHED FILES ARE THE RESULT OF YEARS OF SCIENTIFIC STUDY COMBINED WITH THE EXPERIENCE OF YEARS"