"Day and night you can hear it, tick-tick, wherever you put it. And it is the same one that shows us the hour to go out and play."
With this riddle we began the day we learned to tell the time.
The clock is one of those ideas that look simple to an adult and are in fact hard to grasp. On the same face, the same twelve numbers mean different things to each of the two hands: "five" means five o'clock for one and twenty-five minutes for the other. That is where the commonest confusion comes from, and it is cleared up not by repetition but by understanding what each hand is for.
So we started from something concrete: the hour we go out to play. When the clock shows something a child is waiting for, the dial stops being an exercise and becomes an instrument.