In 1729 Isaac Greenwood published an arithmetic that included  "vulgar" and decimal fractions with the "appreciation thereof to a Variety of cases in Trade and Commerce" of Boston.  Today we recognize his book as one of the first and very best early math books printed in the Colonies.  He included calculations of cube and square roots, taxes, exchange of money, and the Rule of 3, all based on algorithms still taught in most schools.  He even presented more challenging mixture problems as well as arithmetic and geometric progressions.

The NCB selected this "age" problem which might still be found in a first algebra course.  To view the complete explanation, please click here.