5.7+1.9-5.7+1.9=how much
5.7+1.9-5.7+1.9=多少
<gadget id="calculator">1.9 - 5.7</gadget>
<output>-3.8</output>

<gadget id="calculator">5.7 + (-3.8) + 1.9</gadget>
<output>3.8</output>

<result>3.8</result>