Arithmetic Training Booklet Set ICS 1920

This is a nice, clean instruction book set, titled: "INTERNATIONAL CORRESPONDENCE SCHOOLS ARITHMETIC 18A-F". Each is a paper back booklet, stapled binding in very good condition, only very light wear on the exterior, pages are clean with some very minor darkening around the outside edges of the pages mostly. 100+ pages, loaded with illustrations and text on the subject, shown, measures 5.9 x 8.9". A very hard to find instruction book set on math, a third and fourth edition set, copyright in 1892-1899 on the third editions by THE COLLIERY ENGINEER COMPANY, part 5 is copyright in 1905 by the Internation Textbook Company. They are a matched set, the edition are as they were available in 1920. These booklets have been stored inside a hardback storage cover over the years, the cover has protected them very well, so they are in very nice condition due to the care taken in storing them. The storage covers are not included as each cover holds about 12 booklets of which I have listed for sale individually or in subject set at this internet store.
One of the ealiest series of home study books that attempted to improve the education of those in the building trades. Audels Builders guides were first printed around 1923 making these study course books a earlier edition to Audels. Though the Audels libraries had nicer coverings, they are much more common than these early trade manuals from 1920 by ICS! Rare!