Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

Which alphabet is a part of our body?

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

You have a 12 liters jug full of water. You have two empty 8 liters and 5 liters jug. How can you divide the water into two equal parts using these jugs?

A girl has as many brothers as sisters, but each brother has only half as many brothers as sisters. How many brothers and sisters are there in the family?

The ages of a father and son add up to 66.
The father's age is the son's age reversed.
How old could they be?
(3 possible solutions).

Find three numbers such that When we multiply three numbers, we will get the prime numbers. The difference between the second and the first number is equal to the third and second.

I come in different shapes and sizes.
Parts of me are curved, other parts are straight.
You can put me anywhere you like,
but there is only one right place for me.
What am I?

How many cubic feet of dirt are in a hole of one foot deep, three feet long, and two feet wide?