6.4*4.2+4.2*4.6-4.2．
6.4*4.2+4.2*4.6-4.2．
<gadget id="calculator">6.4 * 4.2</gadget>
<output>26.88</output>

<gadget id="calculator">4.2 * 4.6</gadget>
<output>19.32</output>

<gadget id="calculator">19.32 - 4.2</gadget>
<output>15.12</output>

<gadget id="calculator">26.88 + 15.12</gadget>
<output>42</output>

<result>42</result>