Question

Express $40$ as a sum of two odd primes.

Answer 1

$40$ can be written as.

$40=1+39$ ($1$ is neither a prime number nor a composite number)

$40=2+38$ ($2$ is an even prime while $38$ is a composite number)

$40=3+37$ Clearly, both $3$ and $37$ are odd prime numbers.

Thus, $40$ can be expressed as sum of $3$ and $37$.