Divisibility by 8

Topic

Prime and Composite Numbers

Definition

A number is divisible by 8 if the last three digits of the number form a number that is divisible by 8.

Description

Divisibility rules are essential tools in the study of prime and composite numbers, which are fundamental concepts in number theory. The rule for divisibility by 8 states that a number is divisible by 8 if the last three digits of the number form a number that is divisible by 8. For example, the number 1,024 is divisible by 8 because the last three digits, 024, form a number that is divisible by 8 (24 ÷ 8 = 3).

Understanding divisibility rules helps in identifying composite numbers, which have more than two distinct positive divisors. For instance, if a number is divisible by 8, it is not a prime number because it has at least three divisors: 1, 8, and the number itself. This knowledge is crucial for various mathematical applications, including factorization, which is the process of breaking down a number into its prime factors. 

An example of a five-digit number that is divisible by 8 is 12,320. The last three digits, 320, form a number that is divisible by 8 (320 ÷ 8 = 40).

For a complete collection of terms related to primes and composites click on this link: Prime and Composites Collection.