Read this word problem.A dolphin was swimming 7 meters below the surface of the ocean. It located a squid and dove down 4 more meters to eat it. What is the location of the dolphin now relative to the surface?To solve the problem, Lamar subtracted −7−(−4) and came up with an answer of −3 meters. Is Lamar correct? Why or why not?Choices:(A) Yes, Lamar is correct.(B) No. The answer should have been 11 meters, not −3 meters, because the sum of the absolute values of the numbers is 11.(C) No. Lamar should have subtracted −7−4 because the dolphin started 7 meters below the surface and dove down 4 more meters.
Q. Read this word problem.A dolphin was swimming 7 meters below the surface of the ocean. It located a squid and dove down 4 more meters to eat it. What is the location of the dolphin now relative to the surface?To solve the problem, Lamar subtracted −7−(−4) and came up with an answer of −3 meters. Is Lamar correct? Why or why not?Choices:(A) Yes, Lamar is correct.(B) No. The answer should have been 11 meters, not −3 meters, because the sum of the absolute values of the numbers is 11.(C) No. Lamar should have subtracted −7−4 because the dolphin started 7 meters below the surface and dove down 4 more meters.
Start Depth: The dolphin starts 7 meters below the surface, so we start with −7 meters.
Diving Down: Diving down 4 more meters means going 4 meters further below the surface, so we add −4 meters to −7 meters.
Calculation: Calculating −7+(−4) gives us −7−4=−11 meters.
Explanation: Lamar's calculation of −7−(−4)=−3 meters is incorrect because subtracting a negative is like adding a positive.
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