The sum of a number and 3.7 is equal to the difference between 11.5 and 2.5. What is this number?
一个数和3.7相加等于11.5与2.5的差，这个数是多少？
<gadget id="calculator">11.5 - 2.5 - 3.7</gadget>
<output>5.3</output>

<result>5.3</result>