The numbers 6, 12, and 18 are all multiples of 6. They are part of the sequence of numbers that can be evenly divided by 6 without leaving a remainder. For example, 6 is the first multiple, 12 is the second, and 18 is the third. These numbers are often used in basic arithmetic and can be found in various mathematical concepts. In addition to being multiples of 6, these numbers have other interesting properties. 12 is known as a highly composite number because it has more divisors than any smaller number. 18 is also significant in geometry, as it represents the number of degrees in a right angle when multiplied by 2.