What is the word or phrase?

When we see 2 but call 10?

If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?

1 dollar = 100 cent
= 10 cent x 10 cent
= 1/10 dollar x 1/10 dollar
= 1/100 dollar
= 1 cent

=> 1 dollar = 1 cent

solve this tricky problem?

Why is 6 afraid of 7?

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

What number should come in place of the question mark below?

Can you divide the below-given shape into four equal and identical pieces?

Intelligence Agency need to break the vault but the problem is that they are not able to break the vault.

On the vault, a text is written as:

31 11 33 33 43 45
21 25
31 24 11 31 51 41

To Break the code Intelligence Agency brings a mathematician named Joseph.
Minutes later he deciphers the code.

Whats the code?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?