Put 12.5 kg of table salt into 37.5 kg of water to dissolve into brine, find the salt content of the brine.
把12.5千克食盐放入37.5千克水中，溶成盐水，求盐水的含盐率．
<gadget id="calculator">12.5 + 37.5</gadget>
<output>50</output>

<gadget id="calculator">12.5 / 50</gadget>
<output>0.25</output>

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

<gadget id="calculator">0.25 * 1</gadget>
<output>0.25</output>

<result>0.25</result>