Place a mathematical symbol between the numerals 5 and 9 in such a way that the resulting number is greater than 5 but smaller than 9.

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?

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

There are 2 sand hourglasses.

The small one can measure 5 hours and the large one can measure 7 hours.

How can we measure 16 hours with 2 sand hourglasses running together ?

A mathematician couple was having a Frappuccino in Starbucks sitting opposite to each other. Suddenly the guy noticed the text written on the paper in front of them and exclaimed that it was wrong. The girl denied it and said it is appropriate. Both are correct. What is written on the paper?

It is deaf, Dumb and Blind!!!

Still, always tells the truth. What is it?

In the given picture, you can find two letters missing. When two particular letters are placed in the missing spots, you get an eight-letter word while reading in the anti-clockwise direction. Can you find out the missing letters and the missing word eventually?

The dirtier I get, the whiter I look. Who am I?

what does this picture(rebus) riddle means ?

Find the next number in the series?
2, 12, 36, 80, 150, 252, 392, _ ?