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

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

I go up and I go down.
I go up towards the beautiful sky and down toward the green ground.
I am present tense.
I am past tense too
Children love me.

Who Am I?

What jumps when it walks and sits when it stands?

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?

I am a five-letter word and comprises two different vowels and three same consonants. I am so strong that I can spoil your entire work.

Can you find out who am I?

I know a nine-letter word having only one vowel.
Do you ?

John was piloting a plane behind a car but was never able to overtake it. Why?

If you say my name, I will no longer exist. What am I?

Twice ten are six of us,

Six are but three of us,

Nine are but four of us;

What can we possibly be?

Would you know more of us?

Twelve are but six of us,

Five are but four, do you see?

What are we?