((1/15)+(1/35)+(1/63))*2(1/7)=how much.
((1/15)+(1/35)+(1/63))*2(1/7)=多少．
<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">15 / 7</gadget>
<output>15/7 = around 2.142857</output>

<gadget id="calculator">(1/15) * (15/7)</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 / 35</gadget>
<output>1/35 = around 0.028571</output>

<gadget id="calculator">(1/35) * (15/7)</gadget>
<output>3/49 = around 0.061224</output>

<gadget id="calculator">1 / 63</gadget>
<output>1/63 = around 0.015873</output>

<gadget id="calculator">(1/63) * (15/7)</gadget>
<output>5/147 = around 0.034014</output>

<gadget id="calculator">(1/7) + (3/49) + (5/147)</gadget>
<output>5/21 = around 0.238095</output>

<result>5/21 = around 0.238095</result>