7. (3 points) Eight students from a school participate in a math competition, and their average score is 82.5 points, with student $A$ scoring 86 points. If student $A$ only scores 74 points, then their average score would decrease by $\qquad$ points.
【Solution】Solution: $(86-74) \div 8$,
$$
\begin{array}{l}
=12 \div 8, \\
=1.5 \text { (points); }
\end{array}
$$

Answer: Their average score decreased by 1.5 points; hence the answer is: 1.5.