It is known that a=b*1.8+32, (a means Fahrenheit temperature, b means Celsius temperature), how much is 68 degrees Fahrenheit equivalent to Celsius.
已知a=b*1.8+32，(a表示华氏温度，b表示摄氏温度)，华氏68度相当于摄氏多少度．
<gadget id="calculator">68 - 32</gadget>
<output>36</output>

<gadget id="calculator">36 / 1.8</gadget>
<output>20</output>

<result>20</result>