Remove 3 (1/8) from (7/8), how much is left
从(7/8)里去掉3个(1/8)，还剩多少
<gadget id="calculator">7 / 8</gadget>
<output>7/8 = around 0.875</output>

<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/8) * 3</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">(7/8) - (3/8)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>