How do you go from 98 to 720 using just one letter?

A man has eighty-one cows ( numbered 1,2,3...81 as such). The beauty is that cow no. 1 gives 1ltr of milk, cow no. 2 gives 2ltrs of milk and so on. The man wants to equally distribute the cows among his nine sons so that each one of them gets the same quantity of milk.

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

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

There is a straight highway. Four different villages lie on that highway. The distance between them is different. The third village is 60km away from the first village; the fourth is 40 km away from the second; the third is 10 km near to the fourth that it is to the second.

Can you calculate the distance between the fourth and the first village ?

We know that the number 7 is the prime followed by a cube. Which next number is also a prime followed by a cube?

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

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

Can you find the ages of a son, father and grandfather based on the following facts?
The sum of the ages of grandfather, father and son is 140 years.
The age of the son in months is the same as the grandfather in years.
The age of the son in days is the same as the father in weeks.

John can fit six large chocolate boxes or nine small chocolate boxes into a carton. How many cartons will he require to put sixty-six chocolate boxes into?