Water is composed of hydrogen and oxygen in a mass ratio of 1:8. How many kg of oxygen is contained in 5.4 kg of water?
水是由氢和氧按1：8的质量比化合而成的．5.4kg的水含氧多少kg．
<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)</gadget>
<output>4.8</output>

<result>4.8</result>