A kind of salt water, the mass ratio of salt to water is 1:4, what is the salt content of this salt water
一种盐水，盐和水的质量比是1：4，这种盐水的含盐率是多少
<gadget id="calculator">1 + 4</gadget>
<output>5</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">100 / 100</gadget>
<output>1</output>

<gadget id="calculator">(1/5) * 1</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>