Father's weight is 70 kg, mother's weight is father's (5/7), and Xiaofang's weight is mother's (3/5). How many kilograms does Xiaofang weigh?
爸爸的体重是70千克，妈妈的体重是爸爸的(5/7)，小芳的体重是妈妈的(3/5)．小芳的体重是多少千克？
<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">70 * (5/7) * (3/5)</gadget>
<output>30</output>

<result>30</result>