Abstract: A balance beam teaching aid illustrates and verifies mathematical operations involving both integer and non-integer numbers. The balance beam includes a base, a balance arm having a center of gravity and graduations disposed on a face at predetermined longitudinally spaced intervals and a suspension system for pivotably suspending the balance arm from the base to permit rotation of the balance arm in the vertical plane and for preventing rotation of the balance arm in the horizontal plane. Substantially two dimensional area-weights formed from a uniform density, uniform thickness material are attached to the balance arm by inserting the area-weights into a pressure-closed slot disposed in a face of the balance arm and extending along the entire length thereof. The area-weights are typically cut from sections of relatively heavy paper which has a rectangular grid imprinted thereon.