Divisibility by 2

How can we tell whether an integer is divisible by 2 with no remainder? If its last digit is even, that is, if the last digit is one of 0, 2, 4, 6 or 8. Let’s look at some examples:

• The number 18 is divisible by 2, because it ends in the even digit 8, and if we work it out, we find that 18 ÷ 2 = 9.
• The number 27 is not divisible by 2, because it ends in the digit 7, and if we work it out, we get 27 ÷ 2 = 13.5, which is not an integer.
• The negative number −30 is also divisible by 2: the rule works for negative numbers too.