The original puzzle
One must build a calendar with the faces of 2 dice. They must be assembled to produce the numbers from 1 to 31, always using both dice (01). How will the digits from 0 to 9 be disposed on the 6 faces of each die ?

The Solution
Another simple but tricky little puzzle, in a class with the Three Lights.
         We must evidently have the digits "0", "1", and "2", on each die,
                   which leaves 3 places on each die, 6 places in all,
                             but we have, unfortunately, 7 digits left to place.
         How long does it take to realize that "9" is an upside-down "6" ?

Pedagogy
Children should be encouraged to build their own dice-calendar,
and use it, by replacing the dice each day.
Little cards could be made for each month of the year.