0.84*8+8.4*(1/5).
0.84*8+8.4*(1/5)．
<gadget id="calculator">0.84 * 8</gadget>
<output>6.72</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">8.4 * (1/5)</gadget>
<output>1.68</output>

<gadget id="calculator">6.72 + 1.68</gadget>
<output>8.4</output>

<result>8.4</result>