Question

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tính

18/31x62/9

35/72x63/20

34/65: 17/15

111/64: 37/40

12/19x41/52:82/19

Answer 1

[HT.Phong (9A5)]

\(\dfrac{18}{31}\times\dfrac{62}{9}\)

\(=\dfrac{18\times62}{31\times9}\)

\(=\dfrac{2\times2}{1}\)

\(=4\)

==============

\(\dfrac{35}{72}\times\dfrac{63}{20}\)

\(=\dfrac{35\times63}{72\times20}\)

\(=\dfrac{7\times7}{8\times4}\)

\(=\dfrac{49}{32}\)

===============

\(\dfrac{34}{65}:\dfrac{17}{15}\)

\(=\dfrac{34}{65}\times\dfrac{15}{17}\)

\(=\dfrac{34\times15}{65\times17}\)

\(=\dfrac{2\times3}{13\times1}\)

\(=\dfrac{6}{13}\)

===========

\(\dfrac{111}{64}:\dfrac{37}{40}\)

\(=\dfrac{111}{64}\times\dfrac{40}{37}\)

\(=\dfrac{111\times40}{64\times37}\)

\(=\dfrac{3\times5}{8\times1}\)

\(=\dfrac{15}{8}\)

=============

\(\dfrac{12}{19}\times\dfrac{41}{52}:\dfrac{82}{19}\)

\(=\dfrac{12}{19}\times\dfrac{41}{52}\times\dfrac{19}{82}\)

\(=\dfrac{12\times41\times19}{19\times52\times82}\)

\(=\dfrac{3\times1\times1}{1\times13\times2}\)

\(=\dfrac{3}{26}\)