This device can be used in a variety of ways to perform many different arithmetical operations. There are four labelled cups plus one arrow cup in the set. Colour-coded printing on the cups provides students with a visual representation of place value. (thousand, hundred, tens and ones). The + and - signs are used for simple calculations. Clockwise direction represents addition while counter clockwise direction represents subtraction. Teachers can select the appropriate number of cups for different grade levels. Grades 5+.