As your math tutor, I’m here to help you break down factor pairs of 840 step by step!
Factor pairs of 840 are any two numbers that, when multiplied together, equal 840. The question to ask is “what two numbers multiplied together equal 840?” Every factor can be paired with another factor, and multiplying the two will result in 840.
To find the factor pairs of 840, follow these steps:
Step 1:
Find the smallest prime number that is larger than 1, and is a factor of 840. 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 840 by the smallest prime factor, in this case, 2:
840 ÷ 2 = 420
2 and 420 will make a new factor pair.
Step 3:
Repeat Steps 1 and 2, using 420 as the new focus. Find the smallest prime factor that isn’t 1, and divide 420 by that number. In this case, 2 is the new smallest prime factor:
420 ÷ 2 = 210
Remember that this new factor pair is only for the factors of 420, not 840. So, to finish the factor pair for 840, you’d multiply 2 and 2 before pairing with 210:
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 840:
(1, 840), (2, 420), (3, 280), (4, 210), (5, 168), (6, 140), (7, 120), (8, 105), (10, 84), (12, 70), (14, 60), (15, 56), (20, 42), (21, 40), (24, 35), (28, 30)
So, to list all the factors of 840: 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 15, 20, 21, 24, 28, 30, 35, 40, 42, 56, 60, 70, 84, 105, 120, 140, 168, 210, 280, 420, 840
The negative factors of 840 would be: -1, -2, -3, -4, -5, -6, -7, -8, -10, -12, -14, -15, -20, -21, -24, -28, -30, -35, -40, -42, -56, -60, -70, -84, -105, -120, -140, -168, -210, -280, -420, -840
Now you’ve got it! A math tutor would always encourage you to practice with different numbers to reinforce your understanding of factor pairs. Try another one!