5. (5 points) The keyboard of type $A$ computer has 104 keys, which is 72 less than twice the number of keys on the keyboard of type $B$ piano. Therefore, the keyboard of type $B$ piano has $\qquad$ keys.
【Analysis】According to the known number that is a few less than a multiple of another number, to find this number, first determine what 2 times the number of keys on a B-type piano is, and then solve it using division.

【Solution】Solution: $(104+72) \div 2$,
$$
\begin{array}{l}
=176 \div 2, \\
=88 \text { (keys); }
\end{array}
$$

Answer: The keyboard of a B-type piano has 88 keys.
Therefore, the answer is: 88.