Xiao Ming buys x diaries, 2.8 yuan each, and pays 10 yuan, how much money will he get back?
小明买x本日记本，每本2.8元，付出10元，找回多少元．
<gadget id="calculator">10 - 2.8</gadget>
<output>7.2</output>

<result>7.2</result>