A:
Positive:
1 x 1278102111 x 116191131 x 41229137 x 345433341 x 37481407 x 314031013 x 126171147 x 11143
Negative:
-1 x -12781021-11 x -1161911-31 x -412291-37 x -345433-341 x -37481-407 x -31403-1013 x -12617-1147 x -11143
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 12,781,021, it is easier to work with a table - it's called factoring from the outside in.
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 | 12,781,021 | |
| -1 | -12,781,021 |
When you multiply two negative numbers together, you get a positive number. That means both the positive and negative numbers are factors of 12,781,021.
Example:
1 x 12,781,021 = 12,781,021
and
-1 x -12,781,021 = 12,781,021
Notice both answers equal 12,781,021
With that explanation out of the way, let's continue. Next, we take the number 12,781,021 and divide it by 2:
12,781,021 ÷ 2 = 6,390,510.5
If the quotient is a whole number, then 2 and 6,390,510.5 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 | 12,781,021 | |
| -1 | -12,781,021 |
Now, we try dividing 12,781,021 by 3:
12,781,021 ÷ 3 = 4,260,340.3333
If the quotient is a whole number, then 3 and 4,260,340.3333 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 | 12,781,021 | |
| -1 | -12,781,021 |
Let's try dividing by 4:
12,781,021 ÷ 4 = 3,195,255.25
If the quotient is a whole number, then 4 and 3,195,255.25 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 | 12,781,021 | |
| -1 | 12,781,021 |
If you did it right, you will end up with this table:
| 1 | 11 | 31 | 37 | 341 | 407 | 1,013 | 1,147 | 11,143 | 12,617 | 31,403 | 37,481 | 345,433 | 412,291 | 1,161,911 | 12,781,021 |
| -1 | -11 | -31 | -37 | -341 | -407 | -1,013 | -1,147 | -11,143 | -12,617 | -31,403 | -37,481 | -345,433 | -412,291 | -1,161,911 | -12,781,021 |
Here are some more numbers to try:
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