How many times can you subtract the number two from the number fifty?

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

What Word am I Looking For ?

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

There is a five-letter word which has 3 consonants(all are same) and 2 different vowels.
Also, something wrong is associated with the word.

Can you name it?

A monk has a very specific ritual for climbing up the steps to the temple. First, he climbs up to the middle step and meditates for 1 minute. Then he climbs up 8 steps and faces east until he hears a bird singing. Then he walks down 12 steps and picks up a pebble. He takes one step up and tosses the pebble over his left shoulder. Now, he walks up the remaining steps three at a time which only takes him 9 paces. How many steps are there?

Why 1729 is a magic number? Answer Logically.

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

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.

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

You Throw The Outside, Cook The Inside
Eat The Outside, Throw The Inside.

What Is It?