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

What's a single-digit number with no value?

In a mathematical quiz, you are asked the following question:

Use three 9s in a mathematical expression without dividing or multiplying to form the number one.

Can you answer the question?

A newspaper is supposed to have 60 pages.Pages 14 and 21 are missing from the newspaper.

Can you tell me , Which other pages won't be there as well ?

A four-digit number (not beginning with 0) can be represented by ABCD. There is one number such that ABCD=A^B*C^D, where A^B means A raised to the B power. Can you find it?

Find out the missing number in the picture attached:

There is one four-digit whole number n, such that the last four digits of n2 are the original number n

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

I am an odd number. Take away a letter and I become even. What number am I?

Can you make the number 24 by utilizing the numbers 1, 3, 4 and 6? You must use one number only one time and you can use mathematical operation symbols anytime anywhere.