The mooncake filling is made of red bean paste and white sugar. The ratio of red bean paste to white sugar is 2:1. Now that there is 450 grams of white sugar, how many kilograms of red bean paste are needed?
月饼馅是用豆沙和白糖合成的，豆沙和白糖的比是2：1，现在白糖450克，需要豆沙多少千克？
<gadget id="calculator">450 * 2</gadget>
<output>900</output>

<result>900</result>