In order for a number to be divisible by 10, which of the following must be true?

For a number to be divisible by 10, it is essential that the last digit of that number is 0. This is a fundamental rule in divisibility that simplifies the process of determining if a number can be evenly divided by 10, which is a base-10 system characteristic.

Understanding this rule is supported by the fact that the number 10 itself consists of the primes 2 and 5, where the last digit being 0 ensures the presence of both factors, thereby confirming the divisibility. Since the only digit that completes this requirement at the end of the number is 0, any digit other than 0 at the end would result in the number being not divisible by 10.

While other conditions regarding the properties of numbers, such as evenness of digits or being a multiple of 5, can be relevant in different contexts, they do not directly address the criteria necessary for divisibility by 10. Therefore, establishing that the last digit is 0 is the critical factor confirming divisibility by 10.