20,12 x 45,2 + 40,24 x 41,27 - 20,12 x 27,77

=20,12 x 45,2 + 2 x 20,12 x 41,27 - 20,12 x 27,77

nhầm đó đây nè:

20,12 x 45,2 + 2 x 20,12 x 41,27 - 20,12 x 27,77

=20,12 x 45,2 +20,12 x 82,54 - 20,12 x 27,77

=20,12 x (45,2 + 82,54 - 27,77)

=20,12 x 99,97

=2011,3964

2012,2012 nha k mình đi mình trả lời đầu tiên đó

A, Sai                    B,Đúng                       C,Sai                                              D,Sai

42 x 36 + 64 x 42

= 42 x ( 64 + 36 )

= 42 x 100

= 4200

42*36+64*42

= 42 x ( 36 + 64 )

= 42 x        100

=      4200

42 x 36 + 64 x 42 = 42 x ( 36 + 64 )

                           = 42 x 100

                           = 4200 

/ là j v.

\(=\left(\dfrac{19}{42}+\dfrac{23}{42}\right)+\left(\dfrac{1}{37}+\dfrac{36}{37}\right)+10\)

=12

a: \(\dfrac{5}{7}=\dfrac{5\cdot11}{7\cdot11}=\dfrac{55}{77}\)

\(\dfrac{9}{11}=\dfrac{9\cdot7}{11\cdot7}=\dfrac{63}{77}\)

b: \(\dfrac{36}{42}=\dfrac{6}{7}=\dfrac{6\cdot9}{7\cdot9}=\dfrac{54}{63}\)

\(-\dfrac{12}{54}=\dfrac{-2}{9}=\dfrac{-2\cdot7}{9\cdot7}=-\dfrac{14}{63}\)

c: \(\dfrac{-11}{30}=\dfrac{-11\cdot4}{30\cdot4}=\dfrac{-44}{120}\)

\(\dfrac{-17}{-40}=\dfrac{17}{40}=\dfrac{17\cdot3}{40\cdot3}=\dfrac{51}{120}\)

d: \(\dfrac{36}{42}=\dfrac{6}{7}=\dfrac{6\cdot3}{7\cdot3}=\dfrac{18}{21}\)

\(\dfrac{-12}{36}=\dfrac{-1}{3}=\dfrac{-1\cdot7}{3\cdot7}=\dfrac{-7}{21}\)