Q: What are the factor combinations of the number 805?

 A:
Positive:   1 x 8055 x 1617 x 11523 x 35
Negative: -1 x -805-5 x -161-7 x -115-23 x -35


How do I find the factor combinations of the number 805?

Unfortunately, there's not simple formula to identifying all of the factors of a number and it can be a tedious process when trying to identify the divisors of larger numbers. To find the factor combinations of the number 805, it is easier to work with a table - it's called factoring from the outside in.

Outside in Factoring

We start by creating a table and writing 1 on the left side and then the number we're trying to find the factors for on the right side in a table. Then, below that, write the numbers as a negative as well.

1 805
-1 -805

Why are the negative numbers included?

When you multiply two negative numbers together, you get a positive number. That means both the positive and negative numbers are factors of 805.

Example:
1 x 805 = 805
and
-1 x -805 = 805
Notice both answers equal 805

With that explanation out of the way, let's continue. Next, we take the number 805 and divide it by 2:

805 ÷ 2 = 402.5

If the quotient is a whole number, then 2 and 402.5 are factors. In this case, the quotient is not a whole number. Don't write anything down and try the next divisor.

Here is what our table should look like at this step:

1 805
-1 -805

Now, we try dividing 805 by 3:

805 ÷ 3 = 268.3333

If the quotient is a whole number, then 3 and 268.3333 are factors. In this case, the quotient is not a whole number. Don't write anything down and try the next divisor.

Here is what our table should look like at this step:

1 805
-1 -805

Let's try dividing by 4:

805 ÷ 4 = 201.25

If the quotient is a whole number, then 4 and 201.25 are factors. In this case, the quotient is not a whole number. Don't write anything down and try the next divisor.

Here is what our table should look like at this step:

1 805
-1 805
Keep dividing by the next highest number until you cannot divide anymore.

If you did it right, you will end up with this table:

1572335115161805
-1-5-7-23-35-115-161-805

More Examples

Here are some more numbers to try:

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