The sum of two numbers is 13.69. If one addend increases by 6.2 and the other addsend decreases by 6.35, what is the sum?
两个数的和是13.69，如果一个加数增加6.2，另一个加数减少6.35，那么和是多少．
<gadget id="calculator">6.2 - 6.35</gadget>
<output>-0.15</output>

<gadget id="calculator">13.69 + (-0.15)</gadget>
<output>13.54</output>

<result>13.54</result>