Ответ:

а)

\(1\frac{13}{18}=\frac{31}{18}\), а \(2\frac{5}{9}=\frac{23}{9}=\frac{46}{18}\).

\(1\frac{13}{18}-2\frac{5}{9}=\frac{31}{18}-\frac{46}{18}=-\frac{15}{18}=-\frac{5}{6}\).

\(1\frac{1}{12}=\frac{13}{12}\).

\(\frac{13}{12}:\left(-\frac{5}{6}\right)=\frac{13}{12}\cdot\left(-\frac{6}{5}\right)=-\frac{13}{10}\).

б)

\(5,4\cdot5,5=29,7\).

\(29,7-3,7=26\).

Ответ: а) \(-\frac{13}{10}\); б) \(26\).