A year ago, Lao Zhang had a house worth 400,000 yuan. Due to his urgent need for cash, he sold it to Lao Li at a 10% discount. A year later, house prices rose by 20%. Think about it, how much did Lao Zhang lose in total?
一年前，老张有一套住房价值40万，由于急需现金，他以九折优惠卖给老李．一年后，房价上涨20%．想一想，老张总共损失多少万元？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">40 * (1/5)</gadget>
<output>8</output>

<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">1 - (9/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">40 * (1/10)</gadget>
<output>4</output>

<gadget id="calculator">8 + 4</gadget>
<output>12</output>

<result>12</result>