The school cafeteria has x kilograms of rice, eat 15 kilograms every day, how many kilograms are left after eating for 6 days.
学校餐厅有大米x千克，每天吃15千克，吃了6天后，还剩下多少千克．
<gadget id="calculator">15 * 6</gadget>
<output>90</output>

<result>90</result>