Zhang Ming weighs 40 kilograms, and lost 10% of his weight after the illness. After he persisted in physical exercise, his weight increased by 10%. What is his current weight in kilograms?
张明体重40千克，病后体重减轻10%，他坚持体育锻炼后，体重又增加10%，现在体重是多少千克
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/10)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">1 + (1/10)</gadget>
<output>11/10 = around 1.1</output>

<gadget id="calculator">40 * (9/10) * (11/10)</gadget>
<output>198/5 = around 39.6</output>

<result>198/5 = around 39.6</result>