The original price of a storybook is 8.60 yuan, and a class buys 51 more of these storybooks, a total of 382.5 yuan. How much is each book cheaper?
一本故事书原价8.60元，某班添置这本故事书51本，共382.5元，每本便宜多少元？
<gadget id="calculator">382.5 / 51</gadget>
<output>7.5</output>

<gadget id="calculator">8.6 - 7.5</gadget>
<output>1.1</output>

<result>1.1</result>