\(\dfrac{3}{14}\cdot\left(-49\right)=-\dfrac{21}{2}\)

\(\dfrac{3}{4}\cdot\dfrac{-18}{25}=-\dfrac{27}{50}\)

\(1\dfrac{2}{3}\cdot3\dfrac{2}{9}=\dfrac{29}{9}\cdot\dfrac{5}{3}=\dfrac{145}{27}\)

\(40\%\cdot\dfrac{20}{9}=\dfrac{40}{100}\cdot\dfrac{20}{9}=\dfrac{40}{45}=\dfrac{8}{9}\)

a, \(-49.\dfrac{3}{14}=-\dfrac{21}{2}\)

b, \(\dfrac{-18}{25}.\dfrac{3}{4}=-\dfrac{27}{50}\)

c, \(3\dfrac{2}{9}.1\dfrac{2}{3}=\dfrac{29}{9}.\dfrac{5}{3}=\dfrac{145}{27}\)

d, \(\dfrac{20}{9}.40\%=\dfrac{20}{9}.\dfrac{40}{100}=\dfrac{8}{9}\)

D

D

1)0,07

2) \(\frac{2}{8}\)=    0,25

\(\frac{3}{4}\)=    0,75

20%  =  0,2

\(\frac{7}{25}\)=     0,28

\(\frac{30}{20}\)=   1,5

\(2\frac{3}{4}\)=     \(\frac{11}{4}\)=     2,75

\(5\frac{3}{5}\)=    \(\frac{28}{5}\)=     5,6

\(6\frac{2}{8}\)=     \(\frac{50}{8}\)=     6,25

3)   \(\frac{2}{10}\)

      \(\frac{9}{1000}\)

4) Tỉ số % của 2 và 5 là : 2:5=0,4=40%

   Tỉ số % của 5 và 4 là : 5:4=1,25=125%

trả lời:

1.ko đơn vị,bảy phần trăm là:0,07

mấy câu khác bạn tham kgaro bạn "murad thần đao"

học tốt

1.C

2.B

3.C

C

B

C

a) \(27^{64}:81^{20}=3^{192}:3^{80}=3^{112}\)

b) \(\left(\dfrac{1}{8}\right)^{20}:\left(\dfrac{1}{16}\right)^9=\left(\dfrac{1}{2}\right)^{60}:\left(\dfrac{1}{2}\right)^{36}=\left(\dfrac{1}{2}\right)^{24}\)

c) \(\dfrac{1}{3}:\dfrac{1}{5}-\dfrac{1}{6}=\dfrac{5}{3}-\dfrac{1}{6}=\dfrac{10}{6}-\dfrac{1}{6}=\dfrac{9}{6}=\dfrac{3}{2}\)

\(\frac{4^{20}}{6^{20}}-\frac{2^{20}}{3^{20}}+\frac{6^{20}}{9^{20}}=\left(\frac{2}{3}\right)^{20}-\left(\frac{2}{3}\right)^{20}+\left(\frac{2}{3}\right)^{20}=\left(\frac{2}{3}\right)^{20}\)

a: \(=\dfrac{4+15}{20}\cdot\dfrac{1}{2}=\dfrac{19}{20}\cdot\dfrac{1}{2}=\dfrac{19}{40}\)

b: \(=\dfrac{13}{20}-\dfrac{1}{4}+\dfrac{5}{20}=\dfrac{18}{20}-\dfrac{1}{4}\)

\(=\dfrac{9}{10}-\dfrac{1}{4}=\dfrac{18}{20}-\dfrac{5}{20}=\dfrac{13}{20}\)