Xiaojun went to the store and bought a pack of milk for 3.5 yuan, and paid 5 yuan, how much should he get back?
小军到商店买了一包3.5元的牛奶，付了5元，应找回多少元．
<gadget id="calculator">5 - 3.5</gadget>
<output>1.5</output>

<result>1.5</result>