Aeris reads the temperature of a liquid in a lab experiment. The temperature of the liquid is 7.2ºF. After 5 hours, she reads the temperature of the liquid again. The temperature of the liquid is now −1.6°F.
 Aeris plots the points on a number line to determine the temperature change between these two readings.
 How much did the temperature decrease?
 Enter your answer as a decimal in the box.
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