A:
Positive:
1 x 2111212155 x 4222424317 x 1241889585 x 2483779739 x 2856853361 x 628153695 x 5713712563 x 16805
Negative:
-1 x -211121215-5 x -42224243-17 x -12418895-85 x -2483779-739 x -285685-3361 x -62815-3695 x -57137-12563 x -16805
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 211,121,215, 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 | 211,121,215 | |
| -1 | -211,121,215 |
When you multiply two negative numbers together, you get a positive number. That means both the positive and negative numbers are factors of 211,121,215.
Example:
1 x 211,121,215 = 211,121,215
and
-1 x -211,121,215 = 211,121,215
Notice both answers equal 211,121,215
With that explanation out of the way, let's continue. Next, we take the number 211,121,215 and divide it by 2:
211,121,215 ÷ 2 = 105,560,607.5
If the quotient is a whole number, then 2 and 105,560,607.5 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 | 211,121,215 | |
| -1 | -211,121,215 |
Now, we try dividing 211,121,215 by 3:
211,121,215 ÷ 3 = 70,373,738.3333
If the quotient is a whole number, then 3 and 70,373,738.3333 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 | 211,121,215 | |
| -1 | -211,121,215 |
Let's try dividing by 4:
211,121,215 ÷ 4 = 52,780,303.75
If the quotient is a whole number, then 4 and 52,780,303.75 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 | 211,121,215 | |
| -1 | 211,121,215 |
If you did it right, you will end up with this table:
| 1 | 5 | 17 | 85 | 739 | 3,361 | 3,695 | 12,563 | 16,805 | 57,137 | 62,815 | 285,685 | 2,483,779 | 12,418,895 | 42,224,243 | 211,121,215 |
| -1 | -5 | -17 | -85 | -739 | -3,361 | -3,695 | -12,563 | -16,805 | -57,137 | -62,815 | -285,685 | -2,483,779 | -12,418,895 | -42,224,243 | -211,121,215 |
Here are some more numbers to try:
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