Using Only Five 5's and any mathematical operator make sum as 37

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.

James ordered a fishing rod, priced at $3.56. Unfortunately, James is an Eskimo who lives in a very remote part of Greenland and the import rules forbid any package longer than 4 feet to be imported. The fishing rod was 4 feet and 1 inch, just a little too long, so how can the fishing rod be mailed to James without breaking the rules? Ideally James would like the fishing rod to arrive in one piece!

In case you were starting to feel confident, this one was meant for third graders in Vietnam. The answer is 66, but we don't blame you for scratching your head about how they got there.

What does this mathematical rebus means ?

The product of three consecutive numbers is 7980.
Then the sum of these consecutive numbers would be?

I throw two dice simultaneously.

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

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?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

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

which number am I?