The school bought 8 tables and 12 chairs for a total of 864 yuan. A table is 90 yuan, how much is a chair?
学校买来8张桌子和12把椅子，共用864元．一张桌子90元，一把椅子多少元钱？
<gadget id="calculator">864 - 720</gadget>
<output>144</output>

<gadget id="calculator">144 / 12</gadget>
<output>12</output>

<result>12</result>