Can You Find the Missing Zero? A Number Puzzle that Will Trick Your Eyes

You see me once in June, twice in November, and not at all in May. What am I?

what does the below rebus means?

Out of three Friends John, Jacob and Jonny one of them is a king, one is a bureaucrat, and one is a Spy.

The king always tells the truth, the bureaucrat always lies, and the Spy can either lie or tell the truth.

John says: Jonny is a bureaucrat
Jacob says: John is a king
Jonny says: I am a Spy

Tell me, Who is the king, who is the bureaucrat, and who is the Spy?

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?

Considering the below equation:

V + II - VI = 10
IV - X + VIII = 20
IV - VII + VI = 30

Then, I + II + III = ?

Every words stands for unique digit that makes the arithmetic equation true

SEVEN + SEVEN + SIX = TWENTY.

What are the digits ?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

What does this mathematical rebus means ?

This is the oldest riddle that I have heard.

Once there was a man who was travelling with a Tiger, goat and grass.
He needs to cross a river that can carry a maximum of two i.e. Man + one of Tiger goat or grass. But the problem is "If he takes the lion with him, the goat will eat grass and if he takes grass with him, the lion will eat the goat".

How can he ensure the safe delivery of all three?