If 3◎2=3*5-2*2, 0.5◎0.7=0.5*5-0.7*2, ...then: 4◎(1.6◎0.5)=how much.
若3◎2=3*5-2*2，0.5◎0.7=0.5*5-0.7*2，…那么：4◎(1.6◎0.5)=多少．
<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<gadget id="calculator">1.6 * 5</gadget>
<output>8</output>

<gadget id="calculator">0.5 * 2</gadget>
<output>1</output>

<gadget id="calculator">8 - 1</gadget>
<output>7</output>

<gadget id="calculator">7 * 2</gadget>
<output>14</output>

<gadget id="calculator">20 - 14</gadget>
<output>6</output>

<result>6</result>