Вариант 19.1. Выполни указанные действия: 1) 5 10/19 : 15/19; 2) 1 1/4 + 4 9/10; 3) 3 1/5 · 1 1/4; 4) 5 2/3 − 3 5/6; 5) 4 2/5 : 1 3/5; 6) 5 5/6 − 2 1/21; 7) 2 2/11 + 2/11; 8) 5 1/3 · 5.

1. \(5\frac{10}{19}:\frac{15}{19}=\frac{105}{19}\cdot\frac{19}{15}=7\).
2. \(1\frac14+4\frac9{10}=\frac54+\frac{49}{10}=\frac{25+98}{20}=\frac{123}{20}=6\frac3{20}\).
3. \(3\frac15\cdot1\frac14=\frac{16}{5}\cdot\frac54=4\).
4. \(5\frac23-3\frac56=\frac{17}{3}-\frac{23}{6}=\frac{34-23}{6}=\frac{11}{6}=1\frac56\).
5. \(4\frac25:1\frac35=\frac{22}{5}:\frac85=\frac{22}{5}\cdot\frac58=\frac{11}{4}=2\frac34\).
6. \(5\frac56-2\frac1{21}=\frac{35}{6}-\frac{43}{21}=\frac{245-86}{42}=\frac{159}{42}=\frac{53}{14}=3\frac{11}{14}\).
7. \(2\frac2{11}+\frac2{11}=\frac{24}{11}+\frac2{11}=\frac{26}{11}=2\frac4{11}\).
8. \(5\frac13\cdot5=\frac{16}{3}\cdot5=\frac{80}{3}=26\frac23\).

Ответ: 1) 7; 2) 6 3/20; 3) 4; 4) 1 5/6; 5) 2 3/4; 6) 3 11/14; 7) 2 4/11; 8) 26 2/3.