12. As part of a science project, Becca measures the width of various seashells that she finds on the shoreline. The table
shows the differences between the actual width of several
shells and the average width of that type of shell. Becca
measures a shell and finds that it is inch thinner than the
average width of that type of shell. Between the differences
of which two shell types is the difference of the last shell
that Becca measured? Explain your reasoning.
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