I’m tall when I’m young, and I’m short when I’m old. What am I?

What do you see in the given picture?

Today, I celebrated my 32nd birthday but I was born in 1972.
How is this possible?

When Jack was six years old he hammered a nail into his favourite tree to mark his height. Ten years later at age sixteen, Jack returned to see how much higher the nail was. If the tree grew by five centimetres each year, how much higher would the nail be?

Solve the counting riddle by identifying the number of triangles in the given picture.

What does this rebus means ?

PROG WORKRESS

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

Find the next number in the following series:
6, 14, 26, 98, __?

What am I?

Which country gets ill every time?