The cafeteria originally had 600 kilograms of rice. After eating bag a, each bag is 40 kilograms. How many kilograms of rice are left?
食堂原有600千克大米，吃掉a袋，每袋40千克，还剩多少千克大米．
<gadget id="calculator">600 - 40</gadget>
<output>560</output>

<result>560</result>