Lerch, Harold H. Active learning experiences for teaching elementary school mathematics / Harold H. Lerch. - Houghton Mifflin Boston 1981 c1981 - ix, 461 p. :ill. ;28 cm. ISBN: 0395297648 (pbk.) Subjects--Topical Terms: Mathematics -- Study and teaching ( Elementary )--QA LC Class. No.: QA135.5.L44