Children from grades 2, 3, 4, 6, and 8 made speeded, bimanual parity (odd/even) judgments of numerals. Response times indicated that from fourth grade on, parity information was retrieved directly from memory. By grade 3, children represented magnitude information as a left-to-right number line which was accessed obligatorily and, by grades 6 and 8, was attenuated by linguistic effect. (Author/KB)