Add salt to 300 grams of brine with a salt content of 10%. At this time, the salt content is 25%. How much salt is added?
将含盐率10%的盐水300克里加盐，这时含盐率为25%，加了多少盐？
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">300 * (1/10)</gadget>
<output>30</output>

<gadget id="calculator">300 - 30</gadget>
<output>270</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">270 / (3/4)</gadget>
<output>360</output>

<gadget id="calculator">360 - 300</gadget>
<output>60</output>

<result>60</result>