The two brothers have the same deposits in the bank. Now the elder brother withdraws 30 yuan and the younger brother deposits 20 yuan. At this time, the elder brother's money is the younger brother's (1/2). How much yuan did the younger brother deposit?
兄弟二人在银行存款相等，现在哥哥取出30元，弟弟存入20元，这时哥哥的钱是弟弟的(1/2)，弟弟原来存了多少元？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">20 * (1/2)</gadget>
<output>10</output>

<gadget id="calculator">10 + 30</gadget>
<output>40</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">40 / (1/2)</gadget>
<output>80</output>

<result>80</result>