a: =7/3*5/4=35/12

b: =21/53

c:=0,4:0,3=4/3

d: =23/120

e: =3/9=1/3

f: =24/48=1/2

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

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

a) 2,04:(-3,12)              c)4:5 3/4

   =-17/23                      = 3/5

b) (-11/2):1,25              d)10 3/7:5 3/14

   =-22/5                         =9/49

Thay tỉ số [-1 1/2].. 1,25 bằng tỉ số nguyên ta được

A /5/6 B /-6/5 C/6/5 D /-5/6

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, 1,2 : 2,24 = \(\frac{1,2}{2,24}=\frac{120}{224}=\frac{15}{28}\)

b, (2 + \(\frac{1}{5}\)) : \(\frac{3}{4}\)= \(\frac{11}{5}:\frac{3}{4}\)= \(\frac{44}{15}\)

c, \(\frac{2}{7}\): 0,42 =\(\frac{2}{7}:\frac{42}{10}=\frac{10}{147}\)

\(0,3:2,5=3:25\)

\(4\dfrac{2}{5}:1\dfrac{1}{3}=\dfrac{22}{5}:\dfrac{4}{3}=33:10\)

\(-3,2:1\dfrac{2}{7}=\dfrac{-16}{5}:\dfrac{9}{7}=112:45\)