| 摘要 |
A calculator for doing multiplication having an integral ball point pen. The calculator includes a ball point pen, an inner cylinder fixedly connected to the ball point pen, and an outer cylinder angularly displaceable relative to the inner cylinder. The inner cylinder has an outer surface which has a peripheral row of multiplier numbers and a plurality of axial rows of product numbers. The outer cylinder has a window for viewing and choosing a multiplier number and an axial slot for viewing the corresponding row of product numbers. The outer cylinder has an axial column of numbers to be multiplied which are disposed alongside the slot.
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