4. (6 points) If the product of the sum and difference of two natural numbers is 23, then the quotient of the sum of these two numbers divided by their difference is . $\qquad$
【Analysis】Since, $23=23 \times 1$, therefore the sum of these two numbers is 23, and the difference is 1, so the quotient of the sum of these two numbers divided by their difference can be found.

【Solution】Since, $23=23 \times 1$,
therefore, the sum of these two numbers is: 23, and the difference is: 1,
so, the quotient of the sum of these two numbers divided by their difference is:
$$
23 \div 1=23 \text {, }
$$

Therefore, the answer is: 23 .