The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

Find the missing number in the image below.

Can you name any English verb that becomes its past tense by simply rearranging the alphabets ?

Can you count the number of quadrilaterals in the picture below?

Name a key which is hardest to turn.

You need to move three matchsticks to form three squares. Can you do it?

There are three boxes on a table. One of the box contains Gold and the other two are empty. A printed message contains in each box. One of the message is true and the other two are lies.

The first box says "The Gold is not here".

The Second box says "The Gold is not here".

The Third box says "The Gold is in the Second box".

Which box has the Gold?

John left on a horse on Thursday , was gone for two days, and came back on Thursday after completing his work. How did that happen?

All of the flowers I have are orchids except two. All of the flowers I have are hibiscuses except two. All of the flowers I have are roses except two.

Can you tell me how many flowers I have?

Considering the below equation:

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

Then, I + II + III = ?