Liu Bin is 12 years old and weighs 58 kilograms. He is an overweight child. He joined a health club and lost an average of 0.6 kilograms per week. According to this calculation, what is Liu Bin's weight in kilograms after four weeks?
刘彬今年12岁，体重是58千克，属超重儿童．他加入一个健康俱乐部，平均每星期减轻0.6千克，照这样计算，四个星期后，刘彬的体重是多少千克．
<gadget id="calculator">0.6 * 4</gadget>
<output>2.4</output>

<gadget id="calculator">58 - 2.4</gadget>
<output>55.6</output>

<result>55.6</result>