Q: What are the factor combinations of the number 7,781?

 A:
Positive:   1 x 778131 x 251
Negative: -1 x -7781-31 x -251


How do I find the factor combinations of the number 7,781?

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 7,781, 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 7,781
-1 -7,781

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 7,781.

Example:
1 x 7,781 = 7,781
and
-1 x -7,781 = 7,781
Notice both answers equal 7,781

With that explanation out of the way, let's continue. Next, we take the number 7,781 and divide it by 2:

7,781 ÷ 2 = 3,890.5

If the quotient is a whole number, then 2 and 3,890.5 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 7,781
-1 -7,781

Now, we try dividing 7,781 by 3:

7,781 ÷ 3 = 2,593.6667

If the quotient is a whole number, then 3 and 2,593.6667 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 7,781
-1 -7,781

Let's try dividing by 4:

7,781 ÷ 4 = 1,945.25

If the quotient is a whole number, then 4 and 1,945.25 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 7,781
-1 7,781
Keep dividing by the next highest number until you cannot divide anymore.

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

1312517,781
-1-31-251-7,781

More Examples

Here are some more numbers to try:

Try the factor calculator

Explore more about the number 7,781:


Ask a Question