Collections : [University of Michigan William L. Clements Library]

Adam R. Barr of Conestoga Township, Pennsylvania, created this mathematics exercise book or cipher book of mathematical operations, rules and theorems, and example problems. Sections labeled with calligraphic lettering include the Single Rule of 3, Double Rule of 3, Simple Interest, Insurance, Commission, Barter, Fellowship, Exchange, Vulgar Fractions, Decimal Fractions, and others.

Adam R. Barr of Conestoga Township, Pennsylvania, created this mathematics exercise book or cipher book of mathematical operations, rules and theorems, and example problems. Sections labeled with calligraphic lettering include the Single Rule of 3, Double Rule of 3, Simple Interest, Insurance, Commission, Barter, Fellowship, Exchange, Vulgar Fractions, Decimal Fractions, and others.