Can you find out which number multiplied by itself will give the output as 12345678987654321?

10+10 and 11+11 can give you the same answer.

Explain how?

If 24H in a D => 24 hours in a day.
What does "64S on CB" stand for?

What number comes next in this sequence:
7 8 5 5 3 4 4 _

Jack and Joseph are well-known golf rivals. One Day during a match, they were level at a score of 30. Jack hit a bad shot and Joseph added 10 to his score. Joseph then hit an awesome shot and he won the game.

How ?

Find the smallest sentence with all the English alphabet.

The captain of a ship was telling this interesting story: "We travelled the sea far and wide. At one time, two of my sailors were standing on opposite sides of the ship. One was looking west and the other one east. And at the same time, they could see each other clearly." How can that be possible?

What occurs twice in a week, once in a year but never in a day?

Replace the question mark with the number below given a simple math problem.

Why is the Hole below a Lock?