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

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

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

Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters?

Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?

Can you write down eight eights so that they add up to one thousand?

A Shopkeeper sold a few chickens to four different customers on a particular day. It was such that each customer purchased half of the remaining chickens and half the chicken more.

Can you find out how many chicken were sold by the shopkeeper on that day if we tell you that the fourth customer bought a single chicken ?

A mules travels the same distance daily.
I noticed that two of his legs travels 10km and the remaining two travels 12km.
Obviously two mules legs cannot be a 2km ahead of the other 2.

The mules is perfectly normal. So how come this be true ?

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?