Step 1: Start with the fraction 18/40.

Step 2: To convert a fraction into a percentage, divide the numerator by the denominator.

18 ÷ 40 = 0.45

Step 3: Multiply the result by 100 to get the percentage.

0.45 × 100 = 45.0%

Final Answer: 18/40 as a percentage is 45.0%.