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

Presents for a Full Year

The popular song named “Twelve Days of Christmas” tells a story in which really many presents are given: One on the first day, two plus one on the second, three plus two plus one on the third, and so on until the twelfth day.

It is not obvious what the total number of presents amounts to. Here, our exhibit may be of some help. We have provided one shape for each of the twelve days, whith as many faces as there are presents given on that day. Place these shapes on the reactangular field, count the empty cells and subtract that number from the are of the reactangle to get the total number of presents given.