8.7+7.6-8.7+7.6=how much.
8.7+7.6-8.7+7.6=多少．
<gadget id="calculator">7.6 - 8.7</gadget>
<output>-1.1</output>

<gadget id="calculator">8.7 + (-1.1) + 7.6</gadget>
<output>15.2</output>

<result>15.2</result>