15 plus twice a number is equal to half of 34. Find this number.
15加上一个数的2倍，等于34的一半，求这个数．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">34 * (1/2)</gadget>
<output>17</output>

<gadget id="calculator">17 - 15</gadget>
<output>2</output>

<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<result>1</result>