A student seat is 20 yuan, and the price of a desk is three times the price of a seat. How much does it cost to buy a table and chairs?
一把学生座椅20元，一张课桌的价钱是一把座椅价钱的3倍．买一套桌椅一共需要多少钱？
<gadget id="calculator">20 * 3</gadget>
<output>60</output>

<gadget id="calculator">60 + 20</gadget>
<output>80</output>

<result>80</result>