What three numbers, none of which is zero, give the same result whether they’re added or multiplied?

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.

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?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

Get total of 120 by using five zeros 0,0,0,0,0 and any one mathematical operator.
Do you ?

I throw two dice simultaneously.

What is the probability of getting a sum as 9 of the two numbers shown?

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not rounded numerals equals 24.

You need to arrange three 7 and mathematical symbols to form number 1?

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?

If a zookeeper had 100 pairs of animals in her zoo, and two pairs of babies are born for each one of the original animals, then (sadly) 23 animals don’t survive, how many animals do you have left in total?