4 plus 75% of a number equals 11.5, find this number.
4加上一个数的75%等于11.5，求这个数．
<gadget id="calculator">11.5 - 4</gadget>
<output>7.5</output>

<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">7.5 / (3/4)</gadget>
<output>10</output>

<result>10</result>