Question

tính thuận tiện

\(\dfrac{3}{7}\)  x  \(\dfrac{9}{20}\)  +   \(\dfrac{11}{7}\)  x \(\dfrac{9}{20}\)       

Answer 1

9/20 x (3/7 + 11/7 )

= 9/20 x 14/7

= 9/20 x 2

= 9/10

Answer 2

9/20.(3/7+11/7)

=9/20.2

=9/10

Answer 3

= ( 3/7 + 11/7 ) x 9/20

= 2 x 9/20 

= 9/10

Answer 4

\(\dfrac{3}{7}\times\dfrac{9}{20}+\dfrac{11}{7}\times\dfrac{9}{20}\)

\(=\dfrac{9}{20}\times(\dfrac{3}{7}+\dfrac{11}{7})\)

\(=\dfrac{9}{20}\times2\)

\(\dfrac{18}{20}=\dfrac{9}{10}\)