Xiao Ming wanted to buy a copy of "Wisdom Paradise" priced at 19.6 yuan, but the money he brought was still 4 yuan short, so he bought a copy of "The Adventures of Little Naughty" priced at 13.9 yuan. How much money is left?
小明想买一本定价为19.6元的《智慧乐园》可是他带的钱还差4元，于是他买了一本定价13.9元的《小淘气历险记》，还剩多少钱？
<gadget id="calculator">15.4 - 13.9</gadget>
<output>1.5</output>

<result>1.5</result>