What is the word or phrase?

John bought 150 chocolates but he misplaced some of them. His Father asked him how many chocolates were misplaced.
He gave the following answer to him:
If you count in pairs, one remains
If you count in threes, two remain
If you count in fours, three remain
If you count in fives, four remain
If you count in sixes, five remain
If you count in sevens, no chocolate remains.

Can you analyze the statements and tell us how many chocolates were lost?

The product of three consecutive numbers is 7980.
Then the sum of these consecutive numbers would be?

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

What is the fastest way to double your money?

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

There are forty elephants and they have forty-fore heads. How can this be possible?

The host of a game show offers the guest a choice of three doors. Behind one is an expensive car, but behind the other two are goats.
After you have chosen one door, he reveals one of the other two doors behind which is a goat (he wouldn't reveal a car).

Now he gives you the chance to switch to the other unrevealed door or stay at your initial choice. You will then get what is behind that door.

You cannot hear the goats from behind the doors, or in any way know which door has the prize.

Should you stay, or switch, or doesn't it matter?

Irene killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

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