Water is composed of hydrogen and oxygen in a mass ratio of 1:7, what is the mass of oxygen
水是由氢和氧按1：7的质量比化合而成的，氧的质量占多少
<gadget id="calculator">1 + 7</gadget>
<output>8</output>

<gadget id="calculator">7 / 8</gadget>
<output>7/8 = around 0.875</output>

<result>7/8 = around 0.875</result>