Is #5 * 7 * 11 + 13 * 17# odd or even, prime or composite?

1 Answer
May 29, 2015

This is a sum of 2 expressions, each of which is a product of odd numbers.

The product of any number of odd numbers is odd, so each of the two expressions is odd.

The sum of two odd numbers is even.

So #5*7*11+13*17# is even and being also greater than 2 is composite, being a product of 2 and some number greater than 1.