Teacher Li brought 200 yuan to buy 25 kilograms of rice and left 50 yuan, how much is it per kilogram of rice.
李老师带200元买了25千克大米后还剩50元，每千克大米多少元．
<gadget id="calculator">200 - 50</gadget>
<output>150</output>

<gadget id="calculator">150 / 25</gadget>
<output>6</output>

<result>6</result>