Xiao Ming buys two bottles of mineral water for 5 yuan in the forest food store, each bottle is 1.80 yuan, how much should the salesperson get back for him?
小明在森林食品店里用5元钱买了两瓶矿泉水，每瓶1.80元，售货员应找回他多少元？
<gadget id="calculator">1.8 * 2</gadget>
<output>3.6</output>

<gadget id="calculator">5 - 3.6</gadget>
<output>1.4</output>

<result>1.4</result>