Xiaoming and Xiaoli have a total of 20.60 yuan. After they each buy the same diary, Xiaoming has 5.40 yuan left, and Xiaoli has 3.20 yuan left. How much did it cost to buy such a diary?
小明和小丽共有20.60元，两人各买一本同样的日记本后，小明还剩5.40元，小丽还剩3.20元．买这样的日记本一共花了多少钱？
<gadget id="calculator">5.4 + 3.2</gadget>
<output>8.6</output>

<gadget id="calculator">20.6 - 8.6</gadget>
<output>12</output>

<result>12</result>