To celebrate Children's Day, Xinhua Bookstore will buy 10 sets of children's encyclopedias for 45 yuan each, and buy 4 sets and get 1 set free. How much will it cost in total?
新华书店为庆祝"六一"儿童节，要买10套儿童百科书，每套45元，买4套送1套．一共要花多少钱？
<gadget id="calculator">10 - 2</gadget>
<output>8</output>

<gadget id="calculator">45 * 8</gadget>
<output>360</output>

<result>360</result>