Simple calculation: 3.125+(6.875-1.72)-3.28.
简算：3.125+(6.875-1.72)-3.28．
<gadget id="calculator">6.875 - 1.72</gadget>
<output>5.155</output>

<gadget id="calculator">5.155 - 3.28</gadget>
<output>1.875</output>

<gadget id="calculator">3.125 + 1.875</gadget>
<output>5</output>

<result>5</result>