Question 6 (d)

Express the following as the sum of two odd primes:
18

Here 18 is an even number

we can get an even number by adding two even number but we only have 2 as an even prime number so this case fails.

Now we can get an even number by adding two odd numbers.

So, the possible cases are:

7 + 11 = 18
5 + 13 = 18