Buying 4 pens and 5 exercise books costs 15.6 yuan. It is known that each pen is 2.4 yuan, so how much is each exercise book.
买4支钢笔和5本练习本共用去15.6元，已知每支钢笔2.4元，那么每本练习本多少元．
<gadget id="calculator">2.4 * 4</gadget>
<output>9.6</output>

<gadget id="calculator">15.6 - 9.6</gadget>
<output>6</output>

<gadget id="calculator">6 / 5</gadget>
<output>6/5 = around 1.2</output>

<result>6/5 = around 1.2</result>