26
Apr 14

## Henry the Haberdasher's Multiplication

Here is Henry Billingsley's definition of multiplication from his 1570 English translation of Euclid's Elements. This version changed Euclid's definition of multiplication from unary to binary and rendered it defective.

According to Henry Billingsley's definition of multiplication, two multiplied by two is two added to itself two times. As two added to itself one time is four (2 + 2 = 4) how can two added to itself two times also be four?

English speaking mathematicians have been quoting an incorrect definition from an English haberdasher for 444 years. How strange is that!? By contrast, 16th century mathematicians from Italy, Germany and France (not haberdashers) translated Euclid's definition of multiplication correctly and kept is unary and preserved Euclid's geometrical definition of multiplication in the form ab = a placed (together) b times.

Yet today, ab is said to be a added to itself b times, just because Henry the Haberdasher said so!

Henry Billingsley's 1570 definition of multiplication (#16) from his translation of Euclid's Elements into English.