a.\(\dfrac{6}{7}+\dfrac{1}{7}.\dfrac{2}{7}+\dfrac{1}{7}.\dfrac{5}{7}\)
\(=\dfrac{6}{7}+\dfrac{1}{7}\left(\dfrac{2}{7}+\dfrac{5}{7}\right)\)
\(=\dfrac{6}{7}+\dfrac{1}{7}.1\)
\(=\dfrac{6}{7}+\dfrac{1}{7}\)
\(=1\)
b.\(\dfrac{4}{9}.\dfrac{13}{3}-\dfrac{4}{3}.\dfrac{40}{9}\)
\(\dfrac{4}{3}.\dfrac{13}{9}-\dfrac{4}{3}.\dfrac{40}{9}\)
\(=\dfrac{4}{3}\left(\dfrac{13}{9}-\dfrac{40}{9}\right)\)
\(=\dfrac{4}{3}.-3\)
\(=-4\)
c.\(6\dfrac{3}{8}+5\dfrac{1}{2}\)
\(=\dfrac{51}{8}+\dfrac{11}{2}\)
\(=\dfrac{51}{8}+\dfrac{44}{8}\)
\(=\dfrac{95}{8}\)
d.\(5\dfrac{3}{7}-2\dfrac{3}{7}\)
\(=\left(5-2\right)+\left(\dfrac{3}{7}-\dfrac{3}{7}\right)\)
\(=3+0\)
\(=3\)
a: \(=\dfrac{6}{7}+\dfrac{1}{7}\left(\dfrac{2}{7}+\dfrac{5}{7}\right)=\dfrac{6}{7}+\dfrac{1}{7}=1\)
b: =4/9(13/3-40/9)
=4/9*(-1/9)
=-1/81
c; =6+3/8+5+1/2
=11+7/8
=95/8
d: =5+3/7-2-3/7=3
a) \(\dfrac{6}{7}+\dfrac{2}{49}+\dfrac{5}{49}\) = \(\dfrac{42}{49}+\dfrac{2}{49}+\dfrac{5}{49}=\dfrac{42+2+5}{49}=\dfrac{49}{49}=1\)
b) \(\dfrac{52}{27}-\dfrac{160}{27}=\dfrac{52-160}{27}=-\dfrac{108}{27}=-4\)
c) \(6\dfrac{3}{8}+5\dfrac{1}{2}=11\dfrac{7}{8}\)
d) \(5\dfrac{3}{7}-2\dfrac{3}{7}=3\)
