1. The problem is to express the decimal number 0.5 as a fraction. 2. Recall that decimals can be converted to fractions by considering the place value of the decimal digits. For 0.5, the digit 5 is in the tenths place. 3. Therefore, 0.5 can be written as \frac{5}{10} because 5 is in the tenths place. 4. Next, simplify the fraction \frac{5}{10} by dividing both numerator and denominator by their greatest common divisor, which is 5. 5. Dividing numerator and denominator by 5, we get \frac{5 \div 5}{10 \div 5} = \frac{1}{2}. 6. Hence, the decimal 0.5 expressed as a fraction in simplest form is \frac{1}{2}.