least common multiple (lcm), if there is a natural number a that can be divided by a natural number b, then a is called a multiple of b, and b is a divisor of a. for two integers, it means that the two numbers share multiples. the smallest one. when calculating the least common multiple, the greatest common divisor is usually used to assist the calculation.

the greatest common divisor, also known as the greatest common factor or the greatest common factor, refers to the largest divisor shared by two or more integers. the greatest common divisor of a, b is marked as (a, b). similarly, the greatest common divisor of a, b, c is marked as (a, b, c). the greatest common divisor of multiple integers also has the same notation. there are many methods to find the greatest common divisor. common ones include prime factorization method, short division method, euclidean division method, and phase replacement and subtraction method. the concept corresponding to the greatest common divisor is the least common multiple. the least common multiple of a, b is recorded as [a, b].