What indicates a number is divisible by 5?

• A. It ends in 0 or 5
• B. It ends in 1 or 3
• C. It is even
• D. The sum of its digits is divisible by 3

Answer: (A)

Multiples of 5 end in 0 or 5 in base ten. That’s because each time you add 5 to a number, the last digit cycles between 0 and 5, and every time you carry over, the pattern repeats. So the quickest test is to look at the last digit: if it’s 0 or 5, the number is divisible by 5.

For example, 20, 75, 5, and 110 all end with 0 or 5, so they’re divisible by 5. Numbers that end in other digits (like 1 or 3) aren’t divisible by 5. Being even isn’t a guarantee for divisibility by 5 (some multiples of 5 are even, like 10, but many are not), and the rule about the sum of digits applies to divisibility by 3, not 5.