When Xiaoying took a math test, she divided a number by 15 and multiplied it by 15. The result was 900. What is the correct answer to this question?
小英在考数学时，把一个数除以15算成乘15了，结果得900，这道题的正确答案是多少．
<gadget id="calculator">900 / 15 / 15</gadget>
<output>4</output>

<result>4</result>