Author(s):
Frank J. Swetz (The Pennsylvania State University)
Humfrey Baker (fl. 1557-1587) was a London schoolteacher and translator of almanacs. His arithmetic text, The Wellspring of Sciences (1562), was extremely popular in its time and went through several editions. The images below are taken from the 1580 edition.
On folio 33, Baker supplied his reader with “proofs” for addition and subtraction.
The “backer rule of three” is explained on folio 47.
The images above are provided courtesy of Columbia University Libraries.
Index to Mathematical Treasures
Frank J. Swetz (The Pennsylvania State University), "Mathematical Treasure: Humfrey Baker's Arithmetic," Convergence (June 2018)