Вариант В1 Выполните действия: a) 108/109 - 75/109 - 12/109; б) 14/187 + 154/187 + 64/187 + 54/187; в) (37/43 - 15/43) - (17/43 - 15/43); г) 18/27 - (5/27 + 9/27 - 6/27).

a) $$ \frac{108}{109} - \frac{75}{109} - \frac{12}{109} = \frac{108-75-12}{109} = \frac{21}{109} $$.

б) $$ \frac{14}{187} + \frac{154}{187} + \frac{64}{187} + \frac{54}{187} = \frac{14+154+64+54}{187} = \frac{286}{187} = \frac{2 \cdot 11 \cdot 13}{11 \cdot 17} = \frac{26}{17} = 1 \frac{9}{17} $$.

в) $$ (\frac{37}{43} - \frac{15}{43}) - (\frac{17}{43} - \frac{15}{43}) = \frac{37-15}{43} - \frac{17-15}{43} = \frac{22}{43} - \frac{2}{43} = \frac{22-2}{43} = \frac{20}{43} $$.

г) $$ \frac{18}{27} - (\frac{5}{27} + \frac{9}{27} - \frac{6}{27}) = \frac{18}{27} - \frac{5+9-6}{27} = \frac{18}{27} - \frac{8}{27} = \frac{18-8}{27} = \frac{10}{27} $$.

Ответ: а) 21/109; б) 1 9/17; в) 20/43; г) 10/27.