A:
Positive:
1 x 212121355 x 42424277 x 303030535 x 606061331 x 640851655 x 128171831 x 115852317 x 9155
Negative:
-1 x -21212135-5 x -4242427-7 x -3030305-35 x -606061-331 x -64085-1655 x -12817-1831 x -11585-2317 x -9155
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 21,212,135, 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 | 21,212,135 | |
| -1 | -21,212,135 |
When you multiply two negative numbers together, you get a positive number. That means both the positive and negative numbers are factors of 21,212,135.
Example:
1 x 21,212,135 = 21,212,135
and
-1 x -21,212,135 = 21,212,135
Notice both answers equal 21,212,135
With that explanation out of the way, let's continue. Next, we take the number 21,212,135 and divide it by 2:
21,212,135 ÷ 2 = 10,606,067.5
If the quotient is a whole number, then 2 and 10,606,067.5 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 | 21,212,135 | |
| -1 | -21,212,135 |
Now, we try dividing 21,212,135 by 3:
21,212,135 ÷ 3 = 7,070,711.6667
If the quotient is a whole number, then 3 and 7,070,711.6667 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 | 21,212,135 | |
| -1 | -21,212,135 |
Let's try dividing by 4:
21,212,135 ÷ 4 = 5,303,033.75
If the quotient is a whole number, then 4 and 5,303,033.75 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 | 21,212,135 | |
| -1 | 21,212,135 |
If you did it right, you will end up with this table:
| 1 | 5 | 7 | 35 | 331 | 1,655 | 1,831 | 2,317 | 9,155 | 11,585 | 12,817 | 64,085 | 606,061 | 3,030,305 | 4,242,427 | 21,212,135 |
| -1 | -5 | -7 | -35 | -331 | -1,655 | -1,831 | -2,317 | -9,155 | -11,585 | -12,817 | -64,085 | -606,061 | -3,030,305 | -4,242,427 | -21,212,135 |
Here are some more numbers to try:
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