You need at least two numbers to find a GCF.
1, 3, 7, 9, 21, 27, 63, 189.
1, 3, 7, 9, 21, 27, 63, 189.
There are many possible answers. The simplest of these is 1 and 189.
How about: 3*189 = 567
3 x 63 = 189 3 + 63 = 66
1 and 189 3 and 63 7 and 27 9 and 21
1 x 189 = 189 3 x 63 = 1897 x 27 = 1899 x 21 = 18921 x 9 = 18927 x 7 = 18963 x 3 = 189189 x 1 = 189
255
Pairs of numbers whose sum is -14 and that are factors of -189 include -7 and -7, and -21 and 7.
The prime numbers (factors) of 189 are: 3 and 7
63, 126, 189 and so on.