The sum of two numbers is 56.8. If one number is increased by 13 and the other number is decreased by 15, what is the sum of the two numbers?
两个数的和是56.8，如果一个数增加13，另一个数减少15，这时两个数的和是多少
<gadget id="calculator">15 - 13</gadget>
<output>2</output>

<gadget id="calculator">56.8 - 2</gadget>
<output>54.8</output>

<result>54.8</result>