a) 2(3)/(15)-1,9+1(7)/(20)

Для решения данного выражения, сначала приведем дроби к общему знаменателю и затем выполним арифметические операции.<br /><br />$2\frac {3}{15}-1,9+1\frac {7}{20}$<br /><br />Сначала приведем дроби к общему знаменателю. Общий знаменатель для 15 и 20 равен 60.<br /><br />$2\frac {3}{15} = 2\frac {12}{60}$<br />$1\frac {7}{20} = 1\frac {21}{60}$<br /><br />Теперь можем выполнить арифметические операции:<br /><br />$2\frac {12}{60} - 1,9 + 1\frac {21}{60} = 2\frac {12}{60} - 1,9 + 1\frac {21}{60} = 2\frac {33}{60} - 1,9 = 2\frac {33}{60} - 1\frac {54}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{60} = 1\frac {79}{