21.6-0.8*4/0.8*4.
21.6-0.8*4/0.8*4．
<gadget id="calculator">4 / 0.8</gadget>
<output>5</output>

<gadget id="calculator">0.8 * 5 * 4</gadget>
<output>16</output>

<gadget id="calculator">21.6 - 16</gadget>
<output>5.6</output>

<result>5.6</result>