2023.72 72 23

$$\frac{23}{72} \div \frac{72}{23} = \frac{23}{72} \cdot \frac{23}{72} = \frac{23 \cdot 23}{72 \cdot 72} = \frac{529}{5184}$$

Ответ: $$\frac{529}{5184}$$.