12(5-3)/23(5•5)

Let's simplify the expression step by step.

1. Start with the expression:
   \( 12(5 - 3) / 23(5 \cdot 5) \)

2. First, simplify the expression inside the parentheses:
   \( 5 - 3 = 2 \)
   So, we have:
   \( 12(2) / 23(5 \cdot 5) \)

3. Then, evaluate \( 5 \cdot 5 \):
   \( 5 \cdot 5 = 25 \)
   Now, the expression becomes:
   \( 12(2) / 23(25) \)

4. Now, multiply:
   \( 12 \cdot 2 = 24 \)
   Thus, we have:
   \( 24 / (23 \cdot 25) \)

5. Now evaluate \( 23 \cdot 25 \):
   \( 23 \cdot 25 = 575 \)

6. Therefore, the expression simplifies to:
   \( 24 / 575 \)

7. Finally, to express this as a fraction, we say:
   \( \frac{24}{575} \)

So, the simplified expression is \( \frac{24}{575} \).