I have eight fingers and two thumbs but I do not live. What Am I?

In a competitive exam, each correct answer could win you 10 points and each wrong answer could lose you 5 points. You sat in the exam and answered all the 20 questions, which were given in the exam.
When you checked the result, you scored 125 marks on the test.

Can you calculate how many answers given by you were wrong?

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

How is a fly different from a mosquito?

A mother is 21 years older than her child. In exactly 6 years from now, the mother will be exactly 5 times as old as the child.
Where's the father?

Why Aeroplane windows are round?

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

It has a long neck, A name of a bird, Feeds on cargo of ships, It's not alive,

What is it?

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?

Can you calculate the probability of getting a sum of six when a dice is thrown twice?