Mr. Wang bought a composition guidance book for each of the 38 students in his class, and spent a total of 456 yuan. Teacher Li also wants to buy one such composition guidance book for each of the 42 students in her class. How much does it cost?
王老师为自己班38名学生每人买了一本作文辅导书，一共花了456元．李老师也想为自己班42名学生每人买了一本这样的作文辅导书，需要多少钱？
<gadget id="calculator">456 / 38</gadget>
<output>12</output>

<gadget id="calculator">12 * 42</gadget>
<output>504</output>

<result>504</result>