Ответ:

  1. \(\frac{2}{5}-\frac{3}{4}=\frac{8-15}{20}=-\frac{7}{20}\).
  2. \(\frac{1}{\frac{1}{24}+\frac{1}{16}}=\frac{1}{\frac{5}{48}}=\frac{48}{5}\).
  3. \(0{,}8:(1-\frac{1}{9})=0{,}8:\frac{8}{9}=0{,}9\).
  4. \(5{,}6:(1{,}9-7{,}5)=5{,}6:(-5{,}6)=-1\).
  5. \((2{,}1\cdot3{,}5):4{,}9=7{,}35:4{,}9=1{,}5\).
  6. \(\frac{(2^7)^5}{(2^8)^4}=2^{35-32}=8\).
  7. \(\frac{2^7\cdot3^7}{2^6\cdot3^5}=2\cdot3^2=18\).
  8. \(3^7:3^4=3^3=27\).
  9. \(2^{-3-13-(-19)}=2^3=8\).
  10. \(3^{-8+12}=3^4=81\).
  11. \((\frac{3}{15}+\frac{8}{15})\cdot6=\frac{11}{15}\cdot6=\frac{22}{5}\).
  12. \((\frac{1}{13}-\frac{11}{4})\cdot26=\frac{4-143}{52}\cdot26=-\frac{139}{2}\).
  13. \(-12\cdot(-8{,}6)-9{,}4=103{,}2-9{,}4=93{,}8\).
  14. \(6\cdot\frac{1}{9}-\frac{11}{3}=\frac{2}{3}-\frac{11}{3}=-3\).
  15. \(3{,}2\cdot(\frac{3}{8}+\frac{5}{8})=3{,}2\).
  16. \(40000\cdot0{,}00009=3{,}6\).
  17. \(0{,}4\cdot(-1000)-7\cdot100+64=-400-700+64=-1036\).
  18. \(0{,}04+0{,}009+0{,}0009=0{,}0499\).