\(5:\dfrac{2}{3}\)\(=5\times\dfrac{3}{2}=\dfrac{5\times3}{2}=\dfrac{15}{2}\)
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\(\dfrac{4}{7}+\dfrac{2}{5}=\dfrac{20}{35}+\dfrac{14}{35}=\dfrac{34}{35}\)
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\(1-\dfrac{17}{21}=\dfrac{21}{21}-\dfrac{17}{21}=\dfrac{4}{21}\)
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