| 摘要 |
A measuring and instructional device containing a base panel having a top surface and perimeter bounded by at least one edge, with the top surface having evenly spaced apart linear rulings perpendicularly disposed to the edge and defining a non-linear standard unit of measure; and a top transparent sheet having a top surface and a perimeter bounded by at least one edge, wherein the top transparent sheet top surface has evenly spaced apart linear rulings perpendicularly disposed to the long edge of the top transparent sheet and defining fractional increments of the non-linear standard unit of measure; wherein the transparent sheet is positionable over the base panel so that the fractional increments of the unit of measure may be aligned with the units of measure to demonstrate the relationship between the unit of measure and the fractional increments thereof.
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