(50,2: 41 5/6 - 18,04: 50 1/9) * 0,05+4,2

$(50,2 :41 \frac{5}{6} -18,04:50 \frac{1}{9}) *0,05+4,2=4,242$

1) $50,2:41 \frac{5}{6}=50 \frac{2}{10}:41 \frac{5}{6}= \frac{502}{10}: \frac{251}{6}= \frac{502}{10}* \frac{6}{251}= \frac{2}{5}* \frac{3}{1}= \frac{6}{5}=1,2$

2) $18,04:50 \frac{1}{9}=18 \frac{4}{100}: 50\frac{1}{9}= \frac{1804}{100}:\frac{451}{9}= \frac{1804}{100}* \frac{9}{451}= \frac{4}{100}*\frac{9}{1}= \frac{36}{100}=0,36$

3) $1,2 - 0,36 = 0,84$

4) $0,84*0,05 = 0,042$

5) $0,042+4,2 = 4,242$