Son las ocho en punto
Nuestra casa. A las ocho.
Son las nueve
To say 7 o'clock, you say, Il est sept heures. To say 8 o'clock, you say, Il est huit heures.
Usually people say 5 to 8 - not 5 to 8 o'clock and NOT 5 of 8 o'clock. More common is digital format e.g 7:50
Son las ocho menos cinco.
Doce en punto. (twelve on the dot)
Las tres de la madrugada
It is short for "of the clock".
son las cinco de la tarde/noche
They say, 8 o clock is the latest that they will meet.
Four hundred in Spanish is "cuatrocientos".
obtuse