Вариант 2, уровень 1: 1) 9/11 + 3/5 : 11/40; 2) 2 1/16 : 3/4 + 1/4; 3) 1 − 3/8 · 3 1/5; 4) −1,75 · (−8,7 + 6,3); 5) −4,5 + 6,24 : 1,6; 6) (17,1 − 2,8) / 2,2.

1. \(\frac{9}{11}+\frac{3}{5}:\frac{11}{40}=\frac{9}{11}+\frac{3}{5}\cdot\frac{40}{11}=\frac{9}{11}+\frac{24}{11}=3\).
2. \(2\frac{1}{16}:\frac{3}{4}+\frac{1}{4}=\frac{33}{16}\cdot\frac{4}{3}+\frac{1}{4}=\frac{11}{4}+\frac{1}{4}=3\).
3. \(1-\frac{3}{8}\cdot3\frac{1}{5}=1-\frac{3}{8}\cdot\frac{16}{5}=1-\frac{6}{5}=-\frac{1}{5}\).
4. \(-1.75\cdot(-8.7+6.3)=-1.75\cdot(-2.4)=4.2\).
5. \(-4.5+6.24:1.6=-4.5+3.9=-0.6\).
6. \((17.1-2.8):2.2=14.3:2.2=6.5\).

Ответ: 1) 3; 2) 3; 3) \(-\frac{1}{5}\); 4) 4,2; 5) −0,6; 6) 6,5.