What is the greatest possible error if Irina measured the weight of her dog as 13 pounds?

A weight reported as 13 pounds is rounded to the nearest whole pound. The actual weight could be as low as 12.5 pounds or as high as 13.5 pounds, so the greatest difference from 13 pounds is 0.5 pounds. Therefore, the greatest possible error is 0.5 pounds, choice B.

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