The bookstore promotes buying 4 sets of popular science books and getting 1 free. The school now wants to buy 30 sets of such popular science books. Each set costs 128 yuan. How much should the school pay?
书店促销买4套科普书送1套，学校现在要购买30套这样的科普书，每套是128元，学校应付多少钱？
<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<gadget id="calculator">30 / 5</gadget>
<output>6</output>

<gadget id="calculator">6 * 4 * 120</gadget>
<output>2_880</output>

<result>2_880</result>