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

I look flat, but I am deep. Hidden realms I shelter. Lives I take, but the food I offer. At times I am beautiful. I can be calm, angry, and turbulent. I have no heart but offer pleasure as well as death. No man can own me, yet I encompass what all men must have. What am I?

Can you find out the next digit in the following series ?

0, 0, 1, 3, 2, 6, 3, 9, 4, 12, 5, ?

What is black when you buy it, red when you use it, and gray when you throw it away?

I’m tall when I’m young, and I’m short when I’m old. What am I?

A professor thinks of two consecutive numbers between 1 and 10.
'A' knows the 1st number and 'B' knows the second number

A: I do not know your number.
B: Nor do I know your number.
A: Now I know.

What are the four solutions for this?

Can you replace the question mark with the correct number in the below table sequence?

How is the moon similar to a dollar?

Outside a massage parlour, there is a board that reads
"I only massage those who do not massage themselves."

Reading the above statement, does the masseur massage himself?

I’m orange, I wear a green hat and I sound like a parrot. What am I?