It is known that A is (2/5) of B, and A is (2/7) of C. How much more is C than B?
已知A是B的(2/5)，A是C的(2/7)，求C比B多百分之几？
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">1 / (2/7)</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / (2/5)</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">(7/2) - (5/2)</gadget>
<output>1</output>

<gadget id="calculator">1 / (5/2)</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>