2. Выполните действия: 1) 2 1/2·(2/15−3 5/6)+1/4; 2) −1 1/7·(4/5+19/20)·(6 5/6+4 2/3); 3) (6 3/8−2 3/4)·(−4)+7/18·9; 4) 9 1/6:(4 1/3−8)+24·3/8.

1. \(2\frac12\left(\frac2{15}-3\frac56\right)+\frac14=\frac52\cdot\left(-\frac{109}{30}\right)+\frac14=-\frac{109}{12}+\frac14=-9\).
2. \(-1\frac17\left(\frac45+\frac{19}{20}\right)\left(6\frac56+4\frac23\right)=-\frac87\cdot\frac{7}{4}\cdot\frac{69}{6}=-23\).
3. \(\left(6\frac38-2\frac34\right)(-4)+\frac7{18}\cdot9=\frac{29}{8}(-4)+\frac72=-\frac{29}{2}+\frac72=-11\).
4. \(9\frac16:\left(4\frac13-8\right)+24\cdot\frac38=\frac{55}{6}:\left(-\frac{11}{3}\right)+9=-\frac52+9=\frac{13}{2}=6\frac12\).

Ответ: 1) −9; 2) −23; 3) −11; 4) 6 1/2.