The product of a number and (2/7) is 1, what is the reciprocal of this number
一个数与(2/7)的乘积是1，这个数的倒数是多少
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<result>2/7 = around 0.285714</result>