Factor pairs of 72 are any two numbers that, when multiplied together, equal 72. The question to ask is “what two numbers multiplied together equal 72?” Every factor can be paired with another factor, and multiplying the two will result in 72.
To find the factor pairs of 72, follow these steps:
Step 1:
Find the smallest prime number that is larger than 1, and is a factor of 72. For reference, the first prime numbers to check are 2, 3, 5, 7, 11, and 13. In this case, the smallest factor that’s a prime number larger than 1 is 2.
Step 2:
Divide 72 by the smallest prime factor, in this case, 2:
72 ÷ 2 = 36
2 and 36 will make a new factor pair.
Step 3:
Repeat Steps 1 and 2, using 36 as the new focus. Find the smallest prime factor that isn’t 1, and divide 36 by that number. In this case, 2 is the new smallest prime factor:
36 ÷ 2 = 18
Remember that this new factor pair is only for the factors of 36, not 72. So, to finish the factor pair for 72, you’d multiply 2 and 2 before pairing with 18:
2 x 2 = 4
Step 4:
Repeat this process until there are no longer any prime factors larger than one to divide by. At the end, you should have the full list of factor pairs.
Here are all the factor pairs for 72:
(1, 72), (2, 36), (3, 24), (4, 18), (6, 12), (8, 9)
So, to list all the factors of 72: 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72
The negative factors of 72 would be: -1, -2, -3, -4, -6, -8, -9, -12, -18, -24, -36, -72