When Xiao Ming did the decimal subtraction problem, he regarded the subtrahend 3.1 as 3.7, and the result was 12.5. What should be the correct result?
小明在做小数减法题时，把减数3.1看成3.7，结果得12.5，正确的结果应该是多少．
<gadget id="calculator">3.7 - 3.1</gadget>
<output>0.6</output>

<gadget id="calculator">12.5 + 0.6</gadget>
<output>13.1</output>

<result>13.1</result>