Lời giải:

a.

\(1,5:2,16=\frac{15}{10}: \frac{216}{100}=\frac{3}{2}: \frac{54}{25}=\frac{3}{2}.\frac{25}{54}=\frac{25}{36}\)

b.

\(4\frac{2}{7}: \frac{3}{5}=\frac{30}{7}:\frac{3}{5}=\frac{30}{7}.\frac{5}{3}=\frac{50}{7}\)

c.

\(\frac{2}{9}: 0,3=\frac{2}{9}: \frac{3}{10}=\frac{2}{9}.\frac{10}{3}=\frac{20}{27}\)

a.1,5:2,16=25:36

b.2/9 :0,31=200:279

a)\(1,5:2,16=15:216=5:72\)

b)\(4\dfrac{2}{7}:\dfrac{3}{5}=\dfrac{30}{7}:\dfrac{3}{5}=\dfrac{30}{7}.\dfrac{5}{3}=\dfrac{50}{7}=50:7\)

c)\(\dfrac{\dfrac{2}{9}}{0,31}=\dfrac{2}{9}:\dfrac{31}{100}=\dfrac{2}{9}.\dfrac{100}{31}=\dfrac{31}{450}=31:450\)

a) \(3,7:4,5=\dfrac{3,7}{4,5}=\dfrac{37}{45}\)

b) \(2\dfrac{1}{3}:4\dfrac{2}{3}=\dfrac{7}{3}:\dfrac{14}{3}=\dfrac{7}{3}\times\dfrac{3}{14}=\dfrac{1}{2}\)

c) \(\dfrac{3}{8}:0,7=\dfrac{3}{8}:\dfrac{7}{10}=\dfrac{3}{8}\times\dfrac{10}{7}=\dfrac{15}{28}\)

d) \(5\dfrac{1}{7}:2\dfrac{1}{3}=\dfrac{36}{7}:\dfrac{7}{3}=\dfrac{36}{7}\times\dfrac{3}{7}=\dfrac{108}{49}\)

a) 1,5 : 2,16 

\(=\frac{15}{10}:\frac{216}{100}=\frac{3}{2}:\frac{54}{25}=\frac{3}{2}.\frac{25}{54}=\frac{25}{36}=25:36\)

Các câu còn lại lm tương tự

a) \(2.04:\left(-3.12\right)=\dfrac{204}{-312}=\dfrac{-17}{26}\)

b) \(\left(-1\dfrac{1}{2}\right):1.25=\dfrac{-3}{2}:\dfrac{5}{4}=\dfrac{-3}{2}\cdot\dfrac{4}{5}=\dfrac{-12}{10}=\dfrac{-6}{5}\)

c) \(4:5\dfrac{3}{4}=4:\dfrac{23}{4}=4\cdot\dfrac{4}{23}=\dfrac{16}{23}\)

d) \(10\dfrac{3}{7}:5\dfrac{3}{14}=\dfrac{73}{7}:\dfrac{73}{14}=\dfrac{2}{1}\)

\(1,5:2,16=150:216\)

\(4\frac{2}{7}:\frac{3}{5}=\frac{30}{7}:\frac{3}{5}=50:7\)

\(\frac{2}{9}:0,31=\frac{2}{9}\times900:0,31\times900=200:279\)

Bài làm:

1)

Ta có:

a)  \(1,5\div2,16=\frac{25}{36}\)

b) \(4\div\frac{\frac{2}{7}}{\frac{3}{5}}=\frac{42}{5}\)

c) \(\frac{2}{9}\div0,31=\frac{200}{279}\)

2) Ta có: \(ad=bc\)

\(\Leftrightarrow\frac{ad}{cd}=\frac{bc}{cd}\)

\(\Rightarrow\frac{a}{c}=\frac{b}{d}\)

2 9 : 0 , 31 = 2 9 : 31 100 = 2 9 . 100 31 = 200 279