What is black when you buy it, red when you use it, and gray when you throw it away?

If Rajina's daughter is my daughter's mom, who am I to Rajina?

Which word is least like the others? Third, fourth, fifth, sixth, seventh, eighth, ninth?

What month of the year has 28 days?

Every words stands for unique digit that makes the arithmetic equation true

SEVEN + SEVEN + SIX = TWENTY.

What are the digits ?

A man walked into a pub and went straight towards the Barman. He asked for a dirty martini from the Barman. The Barman thought something and then pulled out a pistol from his drawer and aimed it directly at the man. Why did he do that?

There are forty elephants and they have forty-fore heads. How can this be possible?

Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10

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

Solve the mathematical equation in the picture below.