7. Add a dot to indicate the repeating part in the decimal part of 0.3198126 to make it a repeating decimal. The largest repeating decimal is $\qquad$ , and the smallest is $\qquad$ .
Reference answer: $0.31 \dot{9} 812 \dot{6}, 0.3198 \dot{1} \dot{6}$

Key point: Repeating decimals -- characteristics of repeating decimals