Q: What are the factor combinations of the number 640,925?

 A:
Positive:   1 x 6409255 x 12818525 x 2563731 x 20675155 x 4135775 x 827
Negative: -1 x -640925-5 x -128185-25 x -25637-31 x -20675-155 x -4135-775 x -827


How do I find the factor combinations of the number 640,925?

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 640,925, 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.

1 640,925
-1 -640,925

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 640,925.

Example:
1 x 640,925 = 640,925
and
-1 x -640,925 = 640,925
Notice both answers equal 640,925

With that explanation out of the way, let's continue. Next, we take the number 640,925 and divide it by 2:

640,925 ÷ 2 = 320,462.5

If the quotient is a whole number, then 2 and 320,462.5 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:

1 640,925
-1 -640,925

Now, we try dividing 640,925 by 3:

640,925 ÷ 3 = 213,641.6667

If the quotient is a whole number, then 3 and 213,641.6667 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:

1 640,925
-1 -640,925

Let's try dividing by 4:

640,925 ÷ 4 = 160,231.25

If the quotient is a whole number, then 4 and 160,231.25 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:

1 640,925
-1 640,925
Keep dividing by the next highest number until you cannot divide anymore.

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

1525311557758274,13520,67525,637128,185640,925
-1-5-25-31-155-775-827-4,135-20,675-25,637-128,185-640,925

More Examples

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