[ Unusual Constructions Common Fractions

How, without any measuring tools, can you measure 50 cm from a string that is $2 / 3$ of a meter long?

#
Try cutting off a quarter of the shoelace.

## Solution

If you cut off a quarter of the shoelace (for this, you need to fold it in half twice), exactly 50 cm will remain. Indeed, $3 / 4 \cdot 2 / 3=1 / 2$.