(7) Write the expanded form of 0.031 with fractions. Then complete the steps to show how to write 0.031 as a fraction. \[ \begin{aligned} 0.031 & =1.000 \times \frac{1}{100}+\square \times \frac{1}{1,000} \\ & =\frac{3}{\square}+\frac{1}{\square} \\ & =\frac{\square}{1,000}+\frac{\square}{1,000} \\ & =\frac{\square}{1,000} \end{aligned} \]

Step 1 ：Write the expanded form of 0.031 with fractions: \(0.031 = 0/10 + 3/100 + 1/1000\)

Step 2 ：Combine the fractions: \(0.031 = 3/100 + 1/1000\)

Step 3 ：Combine the fractions again: \(0.031 = 31/1000\)

Step 4 ：Find the greatest common divisor (GCD) of 31 and 1000. The GCD is 1, which means that 31 and 1000 are coprime, i.e., the only positive integer that divides both of them is 1.

Step 5 ：Since the GCD is 1, the fraction 31/1000 is already in its simplest form.

Step 6 ：Final Answer: The fraction form of 0.031 is \(\boxed{\frac{31}{1000}}\)