What word is pronounced the same if you take away four of its five letters?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

I have Rs.50 and I spend it in the way as below.

Assume the given figure to be a delicious doughnut. Yes, now you can concentrate more on the puzzle. So you have this delicious doughnut in your refrigerator when your friends come knocking at the door. There are eight of them. Now you have to make three cuts in this doughnut so that each one of you nine people can enjoy a piece of it. Neither you nor your friends would mind the size of their piece as long as they are getting it. How will you do it?

What does below chemistry rebus means?

I am a five-letter word under you,
Remove the first letter and I am above you,
Remove the second as well and I am around you.

Who am I?

In a jungle where there are no street lights or any other artificial source of lights, I notice a black snake crossing the road.
How did I get sight of the snake?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

Find The Next Number in this series.
1, 2, 6, 42, 1806 ?

Can you solve the maths in the below-given picture equation?