Xiao Pang brought some money to buy exercise books. If he bought a 2.4 yuan exercise book, he would have 0.6 yuan left; if he bought a 1.85 yuan exercise book instead, how much money would he have left?
小胖带了一些钱去买练习本，如果买一本2.4元的练习本，可以剩下0.6元；如果改买一本1.85元的练习本，可以剩下多少元？
<gadget id="calculator">0.6 - 1.85</gadget>
<output>-1.25</output>

<gadget id="calculator">2.4 + (-1.25)</gadget>
<output>1.15</output>

<result>1.15</result>