The sum of two addends is 9.58, one of which is 2.99, and what is the other addend.
两个加数的和是9.58，其中一个加数是2.99，另一个加数是多少．
<gadget id="calculator">9.58 - 2.99</gadget>
<output>6.59</output>

<result>6.59</result>