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

From a pack of 52 cards, I placed 4 cards on the table.

I will give you 4 clues about the cards:

Clue 1: Card on left cannot be greater than the card on the right.
Clue 2: Difference between the 1st card and 3rd card is 8.
Clue 3: There is no card of an ace.
Clue 4: There are no face cards (queen, king, jacks).
Clue 5: Difference between the 2nd card and 4th card is 7.

Identify four cards?

Can you decipher the below rebus?

PBLUESAISNUERSES

How can a man go eight days without sleep?

How do you go from 98 to 720 using just one letter?

Find the next number in the sequence

5 12 24 36 ?

A sundial has the fewest moving parts of any timepiece. Which has the most?

John is a strange liar.

He lies on six days of the week, but on the seventh day, he always tells the truth.

He made the following statements on three successive days:

Day 1: "I lie on Monday and Tuesday."
Day 2: "Today, it"s Thursday, Saturday, or Sunday."
Day 3: "I lie on Wednesday and Friday."

On which day does John tell the truth?

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?

Why are all black people so quick ?