Dongdong went to Xinmart Supermarket and bought 5 water-based pens and 3 exercise books for a total of 13.5 yuan. The price of each school water-based pen is 1.5 yuan, how much is the price of each exercise book? (First use the arithmetic method to solve it, and then use the equation to solve it.)
东东去新玛特超市买了5枝水性笔和3本练习本一共用去13.5元．每校水性笔的价钱是1.5元，每本练习本的价钱是多少元？(先用算术方法解，再用方程解．)
<gadget id="calculator">1.5 * 5</gadget>
<output>7.5</output>

<gadget id="calculator">13.5 - 7.5</gadget>
<output>6</output>

<gadget id="calculator">1.5 * 3</gadget>
<output>4.5</output>

<gadget id="calculator">13.5 - 4.5</gadget>
<output>9</output>

<gadget id="calculator">9 / 3</gadget>
<output>3</output>

<gadget id="calculator">6 / 3</gadget>
<output>2</output>

<result>2</result>