I am white when I am dirty, and black when I am clean. What am I?

Can you write down eight eights so that they add up to one thousand?

I don't get anymore wetter, no matter how much rain falls on me.

Pronounced as one letter,
And written with three,
Two letters there are,
And two only in me.
I am double, I am single,
I am black blue and grey,
I am read from both ends,
And the same either way.

I look flat, but I am deep. Hidden realms I shelter. Lives I take, but the food I offer. At times I am beautiful. I can be calm, angry, and turbulent. I have no heart but offer pleasure as well as death. No man can own me, yet I encompass what all men must have. What am I?

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

Without looking at a calendar, within a minute name, a boy's name using 5 consecutive 1st letters of 5 consecutive months

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?