A student chair is 55 yuan, a student desk is 85 yuan, how much does it cost to buy 6 sets of such student desks and chairs?
一把学生椅55元，一张学生课桌85元，购买6套这样的学生桌椅，一共要多少元？
<gadget id="calculator">55 + 85</gadget>
<output>140</output>

<gadget id="calculator">140 * 6</gadget>
<output>840</output>

<result>840</result>