An experimental study to determine the relative difficulty of the elementary number combinations in addition and multiplication This book, "An experimental study to determine the relative difficulty of the elementary number combinations in addition and multiplication", by Harry Vance Holloway, is a replication of a book originally published before 1915. It has been restored by human beings, page by page, so that you may enjoy it in a form as close to the original as possible. This book was created using print-on-demand technology. Thank you for supporting classic literature.