Fill in the box to make a true statement. \[ (5)^{\square}=\frac{1}{125} \]

Step 1 ：The equation is asking for the exponent that when applied to 5 will result in 1/125.

Step 2 ：This is equivalent to asking for the exponent that when applied to 5 will result in \(5^{-3}\), since 1/125 is the same as \(5^{-3}\).

Step 3 ：Therefore, the exponent we are looking for is -3.

Step 4 ：The exponent calculated is -3.0000000000000004, which is very close to -3. The slight difference is due to the precision limit of floating point numbers.

Step 5 ：Therefore, we can conclude that the exponent is -3.

Step 6 ：Final Answer: \(\boxed{-3}\)