The school needs to buy 80 sets of desks and stools, each stool is 45 yuan, and the unit price of the desk is four times that of the stools. How much does the school need to buy these desks and chairs?
学校要添置80套课桌凳，凳子每条45元，桌子的单价是凳子的4倍，学校买这些课桌椅共需要多少钱？
<gadget id="calculator">45 * 4</gadget>
<output>180</output>

<gadget id="calculator">180 + 45</gadget>
<output>225</output>

<gadget id="calculator">225 * 80</gadget>
<output>18_000</output>

<result>18_000</result>