# The Symbol for Pi Isn’t Pi! (Or is it?)

Posted by Greg MacDonald on

One of the charts used as we tell The Story of Our Numerals depicts Ancient Greek Numerals.  Upon inspection (and comparison with the text of the story), it seems that although the story states that the symbol used by the Ancient Greeks to represent the numeral “5” was pi  (the first letter of the Ancient Greek word for five, pente), the chart, appears to depict the Greek letter gamma for the numeral 5!

So what’s going on?

The Ancient Greeks had 2 different numerals systems, one of which succeeded the other.  First came the Acrophonic system (also called Attic or Herodian), then later, the Ionic system (also called Alphabetic, Milesian, or Alexandrian).

The Montessori elementary chart utilizes Acrophonic symbols, which (as the story states) represented five with the Greek letter pi.

The Acrophonic symbol for 5 was   , the symbol for the Ancient Greek letter pi that was in use at the time.  This symbol eventually evolved to the symbol for pi that we know today: .  The original symbol for pi does however, bear an unfortunate resemblance to the modern symbol for gamma that evolved from different roots.

In simplest form, gamma was written as .  This simplest form is often given a decorative serif, (  ) which adds to the confusion, as this makes the letter more closely resemble the earlier version of pi that is used on the chart.

So we have here something for the observant child, who detects this anomaly, to research!  (“It sure looks like my teacher has an error on this chart ...”)

As a note here, the Ionic system matched numbers to letters in the Greek alphabet, so the symbol for 5 became epsilon in this system.  This system also used various punctuation marks, such as the apostrophe and comma, to symbolize numerals up to 999.  This is an alternative study that the children may like to pursue.

And of course, the evolution of the ancient Greek alphabet is yet another research project that may suggest itself as the children conduct their explorations!