Xiaoli wants to buy a set of 5 "Encyclopedia" books, a set of 23.2 yuan. Xiaoli saved enough money to buy books, and happened to be on sale at the bookstore, and this set of books only sold for 17.4 yuan. Xiaoli bought 2 pens with the remaining money. How much is each pen?
小丽想买5本一套的《百科全书》丛书，一套23.2元．小丽攒够了钱去买书，刚好遇上书店促销，这套书只售17.4元．小丽就用剩下的钱买了2支笔．求每支笔多少钱？
<gadget id="calculator">23.2 - 17.4</gadget>
<output>5.8</output>

<gadget id="calculator">5.8 / 2</gadget>
<output>2.9</output>

<result>2.9</result>