4. (8 points) The sum of 5 natural numbers, each consisting only of the digit 8, is 1000. The difference between the largest number and the second largest number is $\qquad$

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4. (8 points) The sum of 5 natural numbers composed only of the digit 8 is 1000, and the difference between the largest number and the second largest number is 
$\underline{800}$.
【Solution】Solution:
$$
\begin{array}{l}
1000=888+88+8+8+8 \\
888-88=800
\end{array}
$$

Therefore, the answer is 800