is 18, twice less than b 4. Then what is the formula for calculating b
a为18，比b的2倍少4．则计算b的算式为多少
<gadget id="calculator">18 + 4</gadget>
<output>22</output>

<gadget id="calculator">22 / 2</gadget>
<output>11</output>

<result>11</result>