An Elementary Arithmetic, Oral and Written

ISBN: 9781333687984 出版年：2016 页码：249 Frank H Hall Forgotten Books

These five processes appear in groups, — five times on page 9 in problems so simple that the tyro will find little difficulty in understanding them; twice on page 10; five times on page 11; four times on page 23; twice on page 25; three times on page 89 twice On page 96; three times on page 109; twice on page 114; three times on page 119; twice on page 146, and at least once on nearly one fourth of the pages of the book. Each of these Spirals is a little more difficult than the preceding one, and each is preparation for the one that follows. The variety in the book comes (1) from the introduction of new terms, (2) from the gradual increase in the difficulty of the problems, and (3) from the different magnitudes (things) to which these processes are applied.