Unusual Constructions

[ Common Fractions

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

#
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, $3 / 4 \cdot 2 / 3=1 / 2$.