A liquid medicine, the ratio of medicine to water is 1:100, now there are 4.5 grams of medicine, how much water is needed?
一种药液，药与水的比例是1：100，现在有4.5克药，需要水多少克？
<gadget id="calculator">100 / 1</gadget>
<output>100</output>

<gadget id="calculator">100 * 4.5</gadget>
<output>450</output>

<result>450</result>