Doce en punto. (twelve on the dot)
You can get the point across several ways. Primarily, you can say "Son las doce". For noon, you can say "mediodía". For midnight, say "medianoche".
Son las nueve
Son las ocho en punto
Nuestra casa. A las ocho.
Son las ocho menos cinco.
Las tres de la madrugada
12'o clock in midday is pm
son las cinco de la tarde/noche
It is short for "of the clock".
Much as don't is the abbreviation for do not.The abbreviation o'clock is the short for "of the clock".So you could say: "It is now 12 of the clock" instead of: "It is now 12 o'clock"
Four hundred in Spanish is "cuatrocientos".
On the digital '24 hour' clock a reading of ' 0000 ' indicates midnight. Depending on the clocks construction, some digital clocks may show ' 2400 '. These times are never user used by airplanes, trains ,military etc., as iot leads to confusion over the day/date. One the '24 hour clock ' the latest time is ' 2359 ' and the earliest time is ' 0001 '. ( 2 minutes later, but a day/date has also changed.