a) ( 7/11 + 5/9 ) x 2
C1 : ( 7/11 + 5/9 ) x 2
= 118/99 x 2
= 236/99
C2 : ( 7/11 + 5/9 ) x 2
= 7/11 x 2 + 5/9 x 2
= 14/11 + 10/9
= 236/99
b) ( 2/3 + 7/9 ) : 2
C1 : ( 2/3 + 7/9 ) : 2
= 13/9 : 2
= 13/18
C2 : ( 2/3 + 7/9 ) : 2
= 2/3 : 2 + 7/9 : 2
= 1/3 + 7/18
= 13/18
a) \(\left(\frac{7}{11}+\frac{5}{9}\right)\times2\)
Cách 1: \(\left(\frac{7}{11}+\frac{5}{9}\right)\times2=\frac{118}{99}\times2=\frac{236}{99}\)
Cách 2: \(\left(\frac{7}{11}+\frac{5}{9}\right)\times2=\frac{7}{11}\times2+\frac{5}{9}\times2=\frac{14}{11}+\frac{10}{9}=\frac{236}{99}\)
b) \(\left(\frac{2}{3}+\frac{7}{9}\right):2\)
Cách 1: \(\left(\frac{2}{3}+\frac{7}{9}\right):2=\frac{13}{9}:2=\frac{13}{18}\)
Cách 2: \(\left(\frac{2}{3}+\frac{7}{9}\right):2=\frac{2}{3}:2+\frac{7}{9}:2=\frac{1}{3}+\frac{7}{18}=\frac{13}{18}\)
a, C1: \(\left(\frac{7}{11}+\frac{5}{9}\right).2=\left(\frac{63}{99}+\frac{55}{99}\right).2=\frac{118}{99}.2=\frac{236}{99}\)
C2: \(=\frac{7}{11}.2+\frac{5}{9}.2=\frac{14}{11}+\frac{10}{9}=\frac{126}{99}+\frac{110}{99}=\frac{236}{99}\)
b, C1: \(\left(\frac{2}{3}+\frac{7}{9}\right):2=\left(\frac{6}{9}+\frac{7}{9}\right).\frac{1}{2}=\frac{13}{9}.\frac{1}{2}=\frac{13}{18}\)
C2: \(\frac{2}{3}:2+\frac{7}{9}:2=\frac{2}{3}.\frac{1}{2}+\frac{7}{9}.\frac{1}{2}=\frac{1}{3}+\frac{7}{18}=\frac{6}{18}+\frac{7}{18}=\frac{13}{18}\)
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