Can anyone tell me a word in the English dictionary which has a silent 'z'?

Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

I am a type of word that is spelt incorrectly or used differently, on purpose for humour. What am I?
Hint 1: You can find me in a joke.
Hint 2: I am a play on words.

John can fit six large chocolate boxes or nine small chocolate boxes into a carton. How many cartons will he require to put sixty-six chocolate boxes into?

A kind heart person buy packed food at 3$/packet from United states and sells them at 1$/packet at Africa. After some time he becomes a millionaire.

How come the guy become millionaire ?

You walk into a creepy house by yourself. There is no electricity, plumbing, or ventilation. Inside you notice 3 doors with numbers on them. Once you open the doors you will die a particular way. Door No.1 You’ll be eaten by a lion who is hungry. Door No.2 You’ll be stabbed to death. Door No.3 There is an electric chair waiting for you. Which door do you pick?

A man is approaching a broad and barren land. He has a package with him. If somehow, he is unable to open the package before reaching the land, he will die.

Can you guess what is present in the package?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?