ESTILONGKATHERINE49GO ESTILONGKATHERINE49GO Math Answered 16. 18 =27 =Common factors:GCF:17. 21 =35 =Common factors:GCF:18. 24 =36 =Common factors:GCF:19. 15 =25 =Common factors:GCF:20. 12 =18 =Common factors:GCF: