A chair is 28 yuan, and a desk is 56 yuan. The school bought 142 sets of desks and chairs. How much less does it cost to buy a chair than to buy a table?
一把椅子28元，一张课桌56元，学校买来142套课桌椅，买椅子比买桌子少花多少钱？
<gadget id="calculator">56 - 28</gadget>
<output>28</output>

<gadget id="calculator">28 * 142</gadget>
<output>3_976</output>

<result>3_976</result>