How can you write nineteen in a manner that if we take out one, it becomes twenty?

Why Aeroplane windows are round?

Samuel was out for a walk when it started to rain. He did not have an umbrella and he wasn't wearing a hat. His clothes were soaked, yet not a single hair on his head got wet. How could this happen?

What two things can you never eat for breakfast?

On her drawing table, Sayna lit 12 coloured candles. A few seconds later she blew two candles off.

How many candles Sayna have at the end?

I am thinking of a five-digit number such that:
The first and last digits are the same, their submission is an even number and multiplication is an odd number and is equal to the fourth number. Subtract five from it and we obtain the second number. Then divide into exact halves and we get the 3rd number.

What number I am thinking of?

using four eights (8) and a one (1) and one mathematical symbol , create the number 100

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

Count the squares in the matchstick puzzle below?

Can you place six X (crosses) in below board without making three in a row in any way ?