As Time Goes By...

As time goes by, we have grown up, a lot.
Just from how a person speak, I predicted a large gap between me and the person. But our age gap is less than 10 years, but I felt that the way the person spoke was just too childish.
Another person, however, only 1 year plus older than me. But from the way the person talk, I felt like I am a small kid.
A few months more, my age will begin with the digit 2. Sounds old.
Time has given young children growth, and elder ones age.
For me, I feel like I am very old, maybe because of my appearance.

When you look at the past, you would feel that time is fast.
When you look at the future, you would feel that time is slow.
When you look at the present, you can feel the time passing second to second.

A friend of mine asked me a mathematics question, the question is as below:
(x-a)(x-b)(x-c).....(x-z), simplified.
It is a tricky question, and difficult to simplified as well. However I managed to answer it, within a time which made me satisfied with myself.
It seems that I still have the intelligence, which I have been seeking.

Guess what's the answer? You'll know it.