The school bought 15 packs of exercise books, each pack of 25 books, and each book costs 0.36 yuan. How much did it cost to buy these exercise books?
学校买来15包练习本，每包25本，每本0.36元，买这些练习本共花多少元？
<gadget id="calculator">25 * 15</gadget>
<output>375</output>

<gadget id="calculator">375 * 0.36</gadget>
<output>135</output>

<result>135</result>