1. The problem asks: A square is divided into 4 equal parts, and 1 part is shaded. What decimal represents the shaded part? 2. The fraction representing the shaded part is $\frac{1}{4}$ because 1 out of 4 equal parts is shaded. 3. To convert the fraction $\frac{1}{4}$ to a decimal, divide the numerator by the denominator: $$\frac{1}{4} = 1 \div 4 = 0.25$$ 4. Therefore, the decimal that represents the shaded part is $0.25$. Final answer: $0.25$