Выполните действия: 1) 2 1/2•(2/15-3 5/6)+1/4

[latex]2 \frac{1}{2} \cdot(\frac{2}{15}-3\frac{5}{6})+\frac{1}{4}= \frac{5}{2} \cdot(\frac{2}{15}-\frac{23}{6})+\frac{1}{4}= \\ \\ = \frac{5}{2} \cdot(\frac{4}{30}-\frac{115}{30})+\frac{1}{4}= \\ \\ = \frac{5}{2} \cdot(-\frac{111}{30})+\frac{15}{60}= -\frac{555}{60}+\frac{15}{60}=-\frac{540}{60}=-9[/latex]