Subtract 5 from a number, add 8, multiply by 6, and finally divide by 4 to get 15. What is the number?
一个数减去5，加上8，再乘6，最后除以4得15，这个数是多少．
<gadget id="calculator">4 / 6</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">15 * (2/3)</gadget>
<output>10</output>

<gadget id="calculator">10 - 8</gadget>
<output>2</output>

<gadget id="calculator">2 + 5</gadget>
<output>7</output>

<result>7</result>