Erlebnisland Mathematik | Technische Sammlungen Dresden | Junghanstraße 1-3 | 01277 Dresden
Erlebnisland Mathematik

Perpetual Calendar

To find out which date falls on what day, first move the left ruler to the correct month and the slider to the height of the correct day. Then put the right ruler on the century number (e.g., on 19 for 1989). Put the right slider to the year (in the example on 89). Add the two numbers in the slider windows. The sum corresponds to a specific day, which you can see in the table at the bottom of the calendar. Gerd Beck, 2000

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