Factor pairs of 1620 are any two numbers that, when multiplied together, equal 1620. The question to ask is “what two numbers multiplied together equal 1620?” Every factor can be paired with another factor, and multiplying the two will result in 1620.
To find the factor pairs of 1620, follow these steps:
Step 1:
Find the smallest prime number that is larger than 1, and is a factor of 1620. 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 1620 by the smallest prime factor, in this case, 2:
1620 ÷ 2 = 810
2 and 810 will make a new factor pair.
Step 3:
Repeat Steps 1 and 2, using 810 as the new focus. Find the smallest prime factor that isn’t 1, and divide 810 by that number. In this case, 2 is the new smallest prime factor:
810 ÷ 2 = 405
Remember that this new factor pair is only for the factors of 810, not 1620. So, to finish the factor pair for 1620, you’d multiply 2 and 2 before pairing with 405:
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 1620:
(1, 1620), (2, 810), (3, 540), (4, 405), (5, 324), (6, 270), (9, 180), (10, 162), (12, 135), (15, 108), (18, 90), (20, 81), (27, 60), (30, 54), (36, 45)
So, to list all the factors of 1620: 1, 2, 3, 4, 5, 6, 9, 10, 12, 15, 18, 20, 27, 30, 36, 45, 54, 60, 81, 90, 108, 135, 162, 180, 270, 324, 405, 540, 810, 1620
The negative factors of 1620 would be: -1, -2, -3, -4, -5, -6, -9, -10, -12, -15, -18, -20, -27, -30, -36, -45, -54, -60, -81, -90, -108, -135, -162, -180, -270, -324, -405, -540, -810, -1620