Ответ:
1)
Сначала вычислим сумму в скобках:
\(1\frac{2}{13}\cdot0.42+0.78\cdot1\frac{2}{13}=1\frac{2}{13}(0.42+0.78)=\frac{15}{13}\cdot1.2=\frac{18}{13}\).
\(\frac{18}{13}\cdot1\frac{4}{9}=\frac{18}{13}\cdot\frac{13}{9}=2\).
\(2:0.6=\frac{10}{3}\), а \(0.5\cdot5\frac{2}{3}=\frac12\cdot\frac{17}{3}=\frac{17}{6}\).
\(\frac{10}{3}-\frac{17}{6}=\frac{20-17}{6}=\frac{1}{2}\).
2)
\(1\frac14+2.25-1\frac{12}{24}=1.25+2.25-1.5=2\).
\(2:4\frac23=2:\frac{14}{3}=\frac37\).
\(2\frac{9}{25}-0.36+0.625=2.36-0.36+0.625=2.625=\frac{21}{8}\).
\(10.6+1\frac25=10.6+1.4=12\).
\(\frac37\cdot\frac{21}{8}\cdot12=\frac{27}{2}=13.5\).
Ответ: 1) \(\frac12\); 2) \(13,5\).
