What is common among 11, 69, and 88?

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

Analyze and find the missing item in the sequence:
16, 06, 68, 88, __, 98

Why 1729 is a magic number? Answer Logically.

This is a most unusual paragraph. How quickly can you find out what is so unusual about it? It looks so ordinary, you'd think nothing was wrong with it. Actually, nothing IS wrong with it. But it is not as ordinary as you might think. If you think about it for a bit, you will find out why it is truly so unusual. So what is it? What is so unordinary about this paragraph?

John was piloting a plane behind a car but was never able to overtake it. Why?

Can you move 2 matchsticks to form four equal sized squares.

Can you find out the smallest number that can be conveyed as the sum of three squares in three unique ways?

A chicken farmer has figured out that a hen and a half can lay an egg and a half in a day and a half. How many hens does the farmer need to produce one dozen eggs in six days?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?