A family giving away their beautiful abacus set! Who could resist? Not me.

As you will see in the photos below, we have an authentic Chinese abacus in pristine condition, inside a box in pristine condition, along with an undated instruction manual that is… well… only a little the worse for wear. You’ll notice that the inside of the box cover is in Chinese, but fortunately the instruction manual is in English. Since it’s from Hong Kong, the English is pretty good (ignore the peculiar typography).

And now I have two special treats for you:

• Everyone (cough, cough) knows how to add and subtract on an abacus. A few Westerners even know how to multiply. Even fewer know how to divide. And only epsilon know how to take square roots on an abacus! So your treat is to see that there are actually instructions for taking cube roots!
• And your puzzle for today is to figure out what number I have represented on the abacus in this photo.

Categories: Math, Teaching & Learning