3-21. Mathematicians altend to precision. What is \( 0.7+\frac{1}{9} \) ? Write your answer as a decimal. Make sure you attend to precision in your answer.

To solve \( 0.7 + \frac{1}{9} \), we first convert \( \frac{1}{9} \) into a decimal, which is approximately \( 0.1111... \). Now, when we add: \[ 0.7 + 0.1111... = 0.8111... \] The sum \( 0.8111... \) can also be expressed as \( 0.81\overline{1} \), indicating that the \( 1 \) repeats indefinitely. However, rounding to two decimal places would yield the result \( 0.81 \). Therefore, to attend to precision effectively, the final answer is: \[ 0.8111... \] or \( 0.81\overline{1} \) if we denote the repeating decimal.