If 8-1.5/(1*(▽+1))=7.5, what is in ▽?
如果8-1.5/(1*(▽+1))=7.5，那么▽里是几？
<gadget id="calculator">8 - 7.5</gadget>
<output>0.5</output>

<gadget id="calculator">1.5 / 0.5 / 1</gadget>
<output>3</output>

<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<result>2</result>