Respuesta :

Kytten
factors of 9: 1, 3, 9 

factors of 63: 1, 3, 7, 9, 21, 63

factors of 27: 1, 3, 9, 27

The greatest factor that all of these numbers have in common is 9.
AnnaR5er
it is 9. 27 and 63 go into nine and nine can go into itself