GMAT Maths Arithmetic - Even and Odd Numbers

An even number is a number whose units digit is 0, 2, 4, 6, or 8. An odd number is a number ending in 1, 3,
5, 7, or 9.You can identify a few helpful patterns about even and odd numbers that often arise on the Quantitative
section:
odd + odd = even

odd × odd = odd

even + even = even

even × even = even

even + odd = odd

even × odd = even