If 2x+1=7, then 4x-1=how much
如果2x+1=7，那么4x-1=多少
<gadget id="calculator">7 - 1</gadget>
<output>6</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">4 * 3</gadget>
<output>12</output>

<gadget id="calculator">12 - 1</gadget>
<output>11</output>

<result>11</result>