When Xiao Ming added a decimal to 13.8, he mistook the plus sign for a minus sign, and the result was 6.52. What should be the correct result?
小明在计算13.8加上一个小数时，把加号错看成了减号，结果为6.52．正确的结果应为多少？
<gadget id="calculator">13.8 - 6.52</gadget>
<output>7.28</output>

<gadget id="calculator">13.8 + 7.28</gadget>
<output>21.08</output>

<result>21.08</result>