x/(3/7)+(1/5)=(4/5).
x/(3/7)+(1/5)=(4/5)．
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">(4/5) * (3/7)</gadget>
<output>12/35 = around 0.342857</output>

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

<gadget id="calculator">(1/5) * (3/7)</gadget>
<output>3/35 = around 0.085714</output>

<gadget id="calculator">(12/35) - (3/35)</gadget>
<output>9/35 = around 0.257143</output>

<result>9/35 = around 0.257143</result>