The factors of 21 are 1, 3, 7 and 21. A factor is a number that can divide evenly into a given number. Because 21 can be divided by numbers other than itself and 1, it is called a composite number.
Know MoreEvery number has 1 and itself as a factor. Numbers that have no other factors are called prime numbers. To determine if 21 has other factors, a person would look to see if it is an even number. Because 21 is not, it cannot be divided by 2. Therefore, the individual would start by dividing by 3. The result is 7, which makes 3 and 7 both factors of 21. Next, 4, 5, and 6 would be tried. None of those can divide evenly into 21, so they are not factors.
Learn more in AlgebraThe factors of 27 are one, three, nine and 27. The factors of a particular number are those numbers that divide evenly into it. One and the number itself are always factors of any given number.
Full Answer >The factors of 9 are 1, 3 and 9. A factor is a number that divides into another number evenly. When a person divides 9 by the numbers 9, 3 and 1, it is easy to see that they are factors.
Full Answer >The factors of 30 are 1, 2, 3, 5, 6, 10, 15 and 30. A number is considered the factor of another number when it can be evenly divided into that number.
Full Answer >The factors of 78 are 1, 2, 3, 6, 13, 26, 39 and 78. The factors of a number are found by breaking the number down into all the combinations of positive integers that can be combined through multiplication to form the number. This is called factorization.
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