(1/2) of the number A is equivalent to the number B. After adding 7.5 to the number B, it is equal to the number A. What is the number B?
甲数的(1/2)相当于乙数，乙数加上7.5以后与甲数相等，乙数是多少．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

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

<gadget id="calculator">7.5 / (1/2)</gadget>
<output>15</output>

<gadget id="calculator">15 - 7.5</gadget>
<output>7.5</output>

<result>7.5</result>