nhanhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh

Lời giải chi tiết :

a ) $\frac{1}{12}$  x $\frac{4}{5}$ 

= $\frac{1X4}{12X5 }$ 

= $\frac{4}{60}$ 

= $\frac{1}{15}$ 

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b ) $\frac{40}{7}$ x $\frac{21}{5}$ 

= $\frac{40X21}{7X5}$ 

= $\frac{840}{35}$ 

= $\frac{24}{1}$ 

= 24

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c ) $\frac{9}{5}$ : $\frac{4}{7}$ 

= $\frac{9}{5}$  x $\frac{7}{4}$ 

= $\frac{9X7}{5X4}$ 

= $\frac{63}{20}$ 

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d ) $\frac{11}{24}$  :  $\frac{44}{3}$ 

= $\frac{11}{24}$ x $\frac{3}{44}$ 

= $\frac{11X3}{24X44}$ 

= $\frac{33}{1056}$ 

= $\frac{1}{32}$ 

HỌC TỐT NHÓ <3

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#chitran3307