00687nam a2200217Ia 450000100060000000300050000600500170001100800410002801000150006902000150008405000230009908200120012210000290013424501090016325000110027226000590028330000210034250000110036350400390037465000560041385487BIBL20160527203752.0741025s1974    caub     b    00110 eng    a 74026511   a057418600X0 aQA135.5b.H42 1974  a372.7/310aHeddens, James W.2Local10aToday's mathematicsba guide to concepts and methods in elementary school mathematicscJames W. Heddens.  a3d ed.0 aPalo Alto, Calif.bScience Research Associatescc1974.  aix, 566 p.bill.  a920901  aIncludes bibliographies and index. 0aMathematicsxStudy and teaching (Elementary)2Local