Hours are h, minutes are min, and seconds are s. Usually, time and minutes are separated by ":",minutes by' and seconds by''.

1, hour: one hour is the unit of time. The hour is not the basic unit of the international system of time units, but an auxiliary unit of time coordinated with the basic unit of the international system of units. Except leap second, one hour is generally equal to 3600 seconds, or 60 minutes, or 1/24 days. "H" is often used in English or mathematics.

2. Minutes: Minutes, also called minutes, are units of measurement of time. Minute is English, which means "tiny" and also means min. Engraving = 15 minutes, word =5 minutes (usage in southern Fujian and Guangdong).

3. Seconds: Seconds is the basic unit of time in the international system of units, with the symbol S, sometimes marked with English abbreviations as sec.

Extended data:

I. Conversion relationship of time units:

1, one day = 1440 minutes, 1 hour =60 minutes, 1 minute =60 seconds.

2, a moment = 15 minutes, a word =5 minutes (usage in southern Fujian and Guangdong).

Second, the angle relationship between clock hands:

1, ordinary clocks and watches are equivalent to a circle, and an hour hand or a minute hand is equivalent to walking through a 360-degree angle.

2. The angle of each big grid on the clock is: 30.

3. The angle of the hour hand every 1 min should be 0.5.

4. The corresponding angle of minute hand every 1 min should be: 6.