If you have a piece of straightedge 121 centimeters long, how
can you cut it into five pieces so that you can measure any integral centimeter
distance of 1 to 121 centimeters. You can only use once each smaller
straightedge you cut during the measurement.
For example, if you cut the straightedge into 1, 15, 25, 35, 45
cm. pieces, you can measure 41 cm. by using the 1, 15, and 25 cm straight edges
together. These three straightedges can also measure 39 cm. by combining
the 15 and 25 cm straightedges, and subtracting 1 cm from it.