It is: 47+52+63+66 = 228/4 => 57 which is the average mean
It is 53.66 recurring.
The average is 38.
Like this.........10 or 26 or 35 or 42 or 57 or 63 or 78 or 81 or 99
-57 + 63 = 6
63
57 + 42 = 99
It is: (63+57)/2 = 60
42 / 63 = 66.666666666667%
6
The GCF is 21.
42 less subtract 21 from 63 , that is to say, 63-21 is 42 so it is 42 less. 63-21 = 42