Ответ:

  1. \(\frac{3}{4}-\frac{4}{5}=\frac{15-16}{20}=-\frac{1}{20}\).
  2. \(\frac{1}{\frac{1}{9}-\frac{1}{12}}=\frac{1}{\frac{1}{36}}=36\).
  3. \(0{,}4:(1-\frac{1}{5})=0{,}4:\frac{4}{5}=0{,}5\).
  4. \((6{,}9-1{,}5):2{,}4=5{,}4:2{,}4=2{,}25\).
  5. \((5{,}6\cdot0{,}3):0{,}8=1{,}68:0{,}8=2{,}1\).
  6. \(\frac{(7^6)^5}{(7^7)^4}=7^{30-28}=49\).
  7. \(\frac{5^9\cdot3^{12}}{3^6\cdot5^6}=5^3\cdot3^6=91125\).
  8. \(4^4:64=256:64=4\).
  9. \(3^{-4-8-(-14)}=3^2=9\).
  10. \(5^{-12-(-11)}=5^{-1}=\frac{1}{5}\).
  11. \((\frac{26}{60}-\frac{33}{60})\cdot\frac{9}{5}=-\frac{7}{60}\cdot\frac{9}{5}=-\frac{21}{100}\).
  12. \(\frac{25}{17}:(\frac{12}{17}+\frac{29}{11})=\frac{25}{17}:\frac{625}{187}=\frac{11}{25}\).
  13. \(4{,}1\cdot7{,}7+0{,}86=31{,}57+0{,}86=32{,}43\).
  14. \(24\cdot\frac{1}{4}+1=7\).
  15. \(2{,}4\cdot(\frac{3}{7}+\frac{4}{7})=2{,}4\).
  16. \(0{,}000125\cdot2000=0{,}25\).
  17. \(80\cdot0{,}0001-6\cdot(-0{,}001)+0{,}5=0{,}008+0{,}006+0{,}5=0{,}514\).
  18. \(0{,}3+0{,}003+0{,}0002=0{,}3032\).