Water is formed by the reaction of hydrogen and oxygen in a mass ratio of 1:8. How many kilograms of hydrogen are needed to produce 54 kilograms of water?
水是由氢气和氧气按1：8的质量比反应生成的．如果要生成54千克的水，需要氢气多少千克．
<gadget id="calculator">1 + 8</gadget>
<output>9</output>

<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">54 * (1/9)</gadget>
<output>6</output>

<result>6</result>