Water is composed of hydrogen and oxygen in a weight ratio of 1:8. There are 5.4 kg of water, how many grams of oxygen are in it?
水是由氢和氧两种元素按1：8的重量比组合的．现有水5.4千克，其中含氧多少克．
<gadget id="calculator">1 + 8</gadget>
<output>9</output>

<gadget id="calculator">8 / 9</gadget>
<output>8/9 = around 0.888889</output>

<gadget id="calculator">5.4 * (8/9) * 1_000</gadget>
<output>4_800</output>

<result>4_800</result>