1 вариант: вычислите: 1) 9/4 + 8/5; 2) 3/4 + 7/25; 3) (11/10 − 4/11) : 15/44; 4) (7/8 − 17/12) : 5/12; 5) 1,8/(1 + 1/11); 6) 19/(5 · 4); 7) (2 1/4 − 1 3/19) · 19; 8) 6 · (1/3)² − 11 · 1/3; 9) (2,7)/(2,9 − 1,1); 10) (7,5 + 3,5)/2,5; 11) (2,8 · 0,3)/0,7; 12) −12 · (−8,6) − 9,4; 13) (7 · 10²)² − (3 · 10⁻⁵).

\(\frac{9}{4}+\frac{8}{5}=\frac{45}{20}+\frac{32}{20}=\frac{77}{20}=3\frac{17}{20}.\)

\(\frac{3}{4}+\frac{7}{25}=\frac{75}{100}+\frac{28}{100}=\frac{103}{100}=1\frac{3}{100}.\)

\(\left(\frac{11}{10}-\frac{4}{11}\right):\frac{15}{44}=\frac{81}{110}\cdot\frac{44}{15}=\frac{54}{25}=2\frac{4}{25}.\)

\(\left(\frac{7}{8}-\frac{17}{12}\right):\frac{5}{12}=\left(-\frac{13}{24}\right)\cdot\frac{12}{5}=-\frac{13}{10}=-1\frac{3}{10}.\)

\(1{,}8:(1+\frac{1}{11})=1{,}8:\frac{12}{11}=1{,}8\cdot\frac{11}{12}=1{,}65.\)

\(19:(5\cdot4)=19:20=0{,}95.\)

\((2\frac{1}{4}-1\frac{3}{19})\cdot19=(\frac{9}{4}-\frac{22}{19})\cdot19=\frac{83}{76}\cdot19=\frac{83}{4}=20\frac{3}{4}.\)

\(6\cdot(\frac{1}{3})^2-11\cdot\frac{1}{3}=\frac{6}{9}-\frac{11}{3}=\frac{2}{3}-\frac{11}{3}=-3.\)

\(2{,}7:(2{,}9-1{,}1)=2{,}7:1{,}8=1{,}5.\)

\((7{,}5+3{,}5):2{,}5=11:2{,}5=4{,}4.\)

\((2{,}8\cdot0{,}3):0{,}7=0{,}84:0{,}7=1{,}2.\)

\(-12\cdot(-8{,}6)-9{,}4=103{,}2-9{,}4=93{,}8.\)

\((7\cdot10^2)^2-(3\cdot10^{-5})=700^2-0{,}00003=489999{,}99997.\)