Xiao Hai went to the store and bought 5 exercise books and some pencils, which cost 9.5 yuan. An exercise book is 1.5 yuan, and a pencil is 0.5 yuan. How many pencils did Xiao Hai buy?
小海到商店买了5本练习本和一些铅笔，共用了9.5元．练习本1.5元一本，铅笔0.5元一支．小海买了几支铅笔？
<gadget id="calculator">1.5 * 5</gadget>
<output>7.5</output>

<gadget id="calculator">9.5 - 7.5</gadget>
<output>2</output>

<gadget id="calculator">2 / 0.5</gadget>
<output>4</output>

<result>4</result>