The school bought 4 sets of desks and chairs this year, each desk is 75 yuan, and each chair is 25 yuan. How much is the total cost?
学校今年买4套办公桌椅，每张办公桌75元，每把椅子25元，一共用去多少元？
<gadget id="calculator">75 + 25</gadget>
<output>100</output>

<gadget id="calculator">100 * 4</gadget>
<output>400</output>

<result>400</result>