Giải:
\(A=\dfrac{7}{14}+\dfrac{5}{15}+\dfrac{10}{60}\)
\(\Leftrightarrow A=\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{6}\)
\(\Leftrightarrow A=\dfrac{3}{6}+\dfrac{2}{6}+\dfrac{1}{6}\)
\(\Leftrightarrow A=\dfrac{3+2+1}{6}\)
\(\Leftrightarrow A=\dfrac{6}{6}=1\)
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