Divisibility by 5

How can we tell whether an integer is divisible by 5? If its last digit is 0 or 5. Examples:

• The number 35 is divisible by 5, because its last digit is 5.
• The number 1480 is divisible by 5, because its last digit is 0.
• The number −75 is divisible by 5, because its last digit is 5 – the rule works for negative numbers too.
• The number 47 is not divisible by 5, because its last digit is neither 0 nor 5.