Algebra Teachers Are Blood-Letters
In medieval times in MoorishSpain, barbers often did bone-setting and bloodletting on the side. And this relates to the history of math?
For example, if you were ill, the barber asked you to grasp a red stick tightly while leeches bled you through an open cut. When not in use, the red stick was hung outside the barber shop, with white bandage coiled around it...thus, the forerunner of the barber pole.
Where's the Math? The barber's offical title at that time was "algebrista," which meant bonesetter or "restorer" of bones.
And the word "algebra" is a Latin variant of the Arabic word "al-jabr" as found in book title Hidab al-jabr wal-muqubala, written by the Arab mathematician Mohammed ibn-Musa al-Khowarizm in 825 A.D.
Furthermore, the words "jabr" and "muqubalah" relate to equation operations: "transpose/ unite" (i.e. 2x-4 = 5-x becomes 3x-4 = 5) and "cancel/balance" (i.e. 2x+4 = x+4 becomes 2x = x).
A final tidbit... the last part of Mohammed ibn-Musa al-Khowarizm's name is the origin for the word "algorithm." Why? Because his book introduced the Arabic numbers (0-9) and the idea of place value, which makes the use of algorithms both possible and efficient.
So, to all of you presently teaching algebra, on with the blood-letting!