The grain store brings in 30 bags of rice and 30 bags of flour, each bag of rice is 50 kilograms, and each bag of flour is 20 kilograms. How many kilograms more rice is brought in than flour?
粮店运进大米和面粉各30袋，每袋大米50千克，每袋面粉20千克，运进的大米比面粉多多少千克？
<gadget id="calculator">50 - 20</gadget>
<output>30</output>

<gadget id="calculator">30 * 30</gadget>
<output>900</output>

<result>900</result>