Use properties of logarithms with the given approximations to evaluate the expression. Use $\log _{b} 2=0.693$ and/or $\log _{b} 9=2.197$ to find $\log _{b} 18$.

Step 1 ：We are given that \(\log_b 2 = 0.693\) and \(\log_b 9 = 2.197\)

Step 2 ：We can express \(\log_b 18\) as \(\log_b 2 + \log_b 9\) due to the property of logarithms that states \(\log_b (xy) = \log_b x + \log_b y\)

Step 3 ：Substituting the given values, we get \(\log_b 18 = 0.693 + 2.197\)

Step 4 ：Adding these values, we find that \(\log_b 18 = 2.89\)

Step 5 ：Final Answer: \(\boxed{2.89}\)