Teacher Wang bought 15 notebooks, paid 30 yuan, and got 3 yuan back. How much is each book?
王老师买了15个本子，付出30元，找回3元．每个本子多少元？
<gadget id="calculator">30 - 3</gadget>
<output>27</output>

<gadget id="calculator">27 / 15</gadget>
<output>9/5 = around 1.8</output>

<result>9/5 = around 1.8</result>