Question

Express the number 84 as the sum of twin primes.

Answer 1

Hint: We first discuss the categorisation and characteristics of prime and a composite number. We find its relation with even and odd numbers. We then express 84 as sum of twin odd primes

Complete step-by-step answer:
The numbers which have only two factors as 1 and that number itself are called prime numbers. The prime numbers are only divisible by 1 and that number.
All other natural numbers other than prime numbers are called composite numbers.
The number of factorisations for prime numbers is always one but for composite numbers it is at least 2.
All even numbers are composite numbers except 2. There aren’t enough smaller numbers than 2 to form the factors of 2. Therefore, it’s considered as prime numbers.
We have to express 84 as the sum of two odd prime numbers.
So, $84=5+79$. Expressing 84 as the sum of twin primes we get 5 and 79.
So, the correct answer is “ 5 and 79”.

Note: Sum of two odd numbers is always even. All prime numbers except 2 are odd. So, if we are taking a sum of two prime numbers other than 2 then we'll always have an even number as the sum.