You can say "los nietos". This includes male and female grandchildren. If you are talking about exclusively female grandchildren, you can use "las nietas".
Abuela
bisabuelos
gran final
Manzana grande.
It literally means children, grand children and great grand children born to a couple, or you could say the family tree.
they way you say grand daughters in spanish is: nieta
muchachos
"Y los hijos" = "And the children"
Translation: Gran momento
como estar
Translation: pez gordo
Niños incapacitados