Xiao Pang bought 4 pencils and 7 exercise books and paid 5.8 yuan in total. If each pencil costs 0.4 yuan, how much is each exercise book?
小胖买了4支铅笔和7本练习本共付5.8元，如果每支铅笔为0.4元，那么每本练习本多少元？
<gadget id="calculator">4 * 0.4</gadget>
<output>1.6</output>

<gadget id="calculator">5.8 - 1.6</gadget>
<output>4.2</output>

<gadget id="calculator">4.2 / 7</gadget>
<output>0.6</output>

<result>0.6</result>