| 摘要 |
A card (20) has a recording surface (36) with three aligned horizontal rows (40,42,44) of boxes. The first row (40) is in the middle with the second row (42) above it and the third row (44) below it. An initial odometer reading of a vehicle is recorded in the first row (40). At the same time, a base fuel gauge reading is taken and is recorded by positioning a pivotable pointer (50) mounted on the card (20) above the first row (40). The vehicle is driven to consume fuel, and ten gallons of fuel are added to bring the fuel gauge reading above the base reading. When the fuel gauge again reaches the base reading, a second odometer reading is taken and recorded in the second row (42) of boxes. The reading in the first row (40) is subtracted from the reading in the second row (42), and the result is written in the third row (44) of boxes. A decimal point (46) is positioned between the two rightmost boxes of the third row (44) to automatically convert the subtraction results into miles per gallon.
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