What is always in front of you but can’t be seen?

How many triangles are there on the puzzle below?

10+10 and 11+11 can give you the same answer.

Explain how?

As easy as you can get into me, it is as hard to get out of me.

Do you know what I am?

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

If we change the South-East direction into North and North-East into West and all others similarly.
Can you find out which direction will be in the place of South-West direction?

Can you decipher the following common phrase?

T M C
A U O
H S M
W T E

Known by all without exception, Forever here, for your protection, Sometimes strong, sometimes weak, Right after the night I come - hot and chic. And while millions of miles away, I always get to you, I find my way. No life around could do without me, Can you guess what I might be?

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

I cannot talk, but I always reply when spoken to. What am I?