In a subtraction formula, the sum of the minuend, the subtrahend and the difference is (6/7), and the minuend must be . How many
一个减法算式中，被减数、减数、差的和是(6/7)，被减数一定是．多少
<gadget id="calculator">6 / 7</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">(6/7) / 2</gadget>
<output>3/7 = around 0.428571</output>

<result>3/7 = around 0.428571</result>