What is the below Rebus indicate?

I noticed one of the words in the oxford dictionary is spelled incorrectly. What about you?

Move four matchsticks to the below square to form three squares?

What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?

You have two buckets of 11 liters and 6 litres.
How can you measure exactly 8 litres?

A girl was sitting in her hotel room when she heard a knock on the door. She opened the door and found that a man was standing outside.
The man said, "Oh! I am really sorry, I thought this was my room."
He then walked through the corridor to the elevator. The girl did not know the man. She closed her door and called security asking them to apprehend the man.
What made her suspicious of that man? He might have been genuinely mistaken.

I never was there, I am always to be.
You have never ever seen me, not ever you will.
Yet I am the confidence of everyone.

Who Am I?

A rubber ball keeps on bouncing back to 2/3 of the height from which it is dropped. Can you calculate the fraction of its original height that the ball will bounce after it is dropped and it has bounced four times without any hindrance ?

An exterior architect is asked by a builder to plant seven trees in a manner that there are exactly six rows of trees in a straight line and each row has three trees in particular.

How will he do it?

When is the top of a mountain similar to a savings account?