How do I check whether a variable has an even numeric value?

Question

How should I change this to check whether val has an even or odd numeric value?

val=2
if $((RANDOM % $val)); ...

Answer 1

$ a=4

$ [ $((a%2)) -eq 0 ] && echo "even"
even

$ a=3

$ [ $((a%2)) -eq 0 ] && echo "even"