How many kilograms of water are added to 3 kilograms of salt to obtain a salt water with a salt content of 3%.
往3千克盐里加入多少千克的水，可得到含盐率为3%的盐水．
<gadget id="calculator">3 / 100</gadget>
<output>3/100 = around 0.03</output>

<gadget id="calculator">3 / (3/100)</gadget>
<output>100</output>

<gadget id="calculator">100 - 3</gadget>
<output>97</output>

<result>97</result>