A bag of rice, use (3/8) in the first month, use (1/8) in the second month, how much is left
一袋大米，第一个月用去(3/8)，第二个月用去(1/8)，还剩多少
<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

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

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

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