There are 20 grams of salt in 100 grams of salt water, the weight of salt is the amount of water
100克盐水中有盐20克，盐的重量是水的多少
<gadget id="calculator">100 - 20</gadget>
<output>80</output>

<gadget id="calculator">20 / 80</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>