4. Use the digits $1$, $9$, $8$, and $5$ to fill in the four boxes below so that their product is maximized.
$$
(\square+\square) \times(\square+\square) \text {. }
$$
(Wenzhou Li Fangyue)
4. $(8+5) \times(1+9)=130$.

Translate the above text into English, please keep the original text's line breaks and format, and output the translation result directly.

4. $(8+5) \times(1+9)=130$.