I am not sure what the last number is
but I think you were asking what is GCF (Greatest common factor) of 9 and 63
The answer is 9.
You would want to list out the factors before you work
9: 1 3 9
63: 1 3 7 9 21 63
So the highest number or factor (that is a whole number that if multiplied by a whole number of something else can give you the specific number). so the answer is 9
P.S. a factor can never be higher than the number itself or in the fractional state like even though 0.25 can give you 1, it is not a factor of one. Must be whole, in some cases like in advanced math, negative numbers are also accepted in certain situations for solving but a factor should not be less than positive 1 or higher than the number it is a factor of