The document discusses factors, multiples, and divisibility of numbers. It defines a number as being divisible by another if the quotient is a whole number with no remainder. A multiple is the product of a number and any whole number greater than zero. A factor is a number that divides another number with no remainder. It provides examples showing 20 is divisible by 4 and 4 is a factor of 20. It also states 15 is a multiple of 3 and 5. Divisibility rules are outlined for numbers being divisible by 2, 3, 4, 5, 6, 9, and 10.