Pedagogico device for calculating basic arithmetic operations. (Machine-translation by Google Translate, not legally binding)

摘要

Device pedagogico for calculating arithmetic operations basic, essentially characterized consist of a plurality of strips doubles overlayed and assembled by one end through a pin eccentric on which pivotable unitarily, existing printed in such end of each strip, un number digit, and parallel to the longitudinal edge of said strips, aligning all digits, spaced and located between pairs of courts to extend cross the edge opposite of strip for whose courts configure tabs levadizas that at rest hiding a guarismo on the result of operation between coordinate aritmetica performed digits. (Machine-translation by Google Translate, not legally binding)