Li Xiaoming used 5 yuan to buy stationery. He bought 2 ballpoint pens, each for 1.5 yuan, and the rest of the money to buy exercise books, each of which was 0.4 yuan. How many exercise books can I buy?
李小明拿5元钱去买文具，买了2支圆珠笔，每支1.5元，剩下的钱买练习本，每本练习本0.4元．可以买多少本练习本？
<gadget id="calculator">1.5 * 2</gadget>
<output>3</output>

<gadget id="calculator">5 - 3</gadget>
<output>2</output>

<gadget id="calculator">2 / 0.4</gadget>
<output>5</output>

<result>5</result>