I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

It belongs to you, but other people use it more than you do. What is it?

Can you find out the total number of triangles in the given figure?

In the addition below, all digits have been replaced by letters. Equal letters represent equal digits and different letters represent different digits.
ABCABA
BBDCAA
ABEABB
ABDBAA
------- +
AAFGBDH
What does the complete addition look like in digits?

If I put in one bird per cage, I have one bird too many. If I put in two bird per cage, I have one cage too many. How many cages and birds do I have?

An exterior architect is asked by a builder to plant seven trees in a manner that there are exactly six rows of trees in a straight line and each row has three trees in particular.

How will he do it?

Name a key which is hardest to turn.

A red house is made out of red bricks. A yellow house is made out of yellow bricks. And, a blue house is made out of blue bricks. So, what is a greenhouse made of?