Any clock has three hands to measure time.
Hour hand goes very slowly around the clock. The minute hand goes much faster around the clock as compared to the hour hand.
In the above picture, hour hand is on 9 and minute hand is on 12, then we can say it is 9 o’ clock. It can be written as 9:00.
In the above picture hour hand is on 5 and minute hand is on 12, then it is 5 o’ clock or 5:00.
Form the above two times we can conclude that when we see the minute hand is on 12, we must look at the hour hand to tell the exact time.