the temperature dropped by −2.5 celsius degrees for 5 consecutive days. what was the total decrease in temperature over the 5-day period, expressed as a signed number?

If the temperature dropped by -2.5 for 5 days, then multiply -2.5 and 5 to get the total decrease. 
(-2.5)(5) = -12.5
Over the 5-day period, the temperature dropped by -12.5 degrees Celsius. 
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