In 2005, my country promulgated a new personal income tax collection standard. Personal income below 1,600 yuan is not taxed. If the monthly income exceeds 1,600 yuan, the excess part will be taxed step by step. If the monthly income exceeds 500 yuan, the personal income tax will be levied at 5%; if the monthly income exceeds 500-2,000 yuan, the personal income tax will be levied at 10%. Xiao Ming's mother has a monthly income of 3,500 yuan. How much personal income tax does she have to pay every month?
2005年我国公布了新的个人收入所得税征收标准．个人收入1600元以下不征税．月收入超过1600元，超过部分分步计税，超过500元的按5%征收个人所得税；超过500-2000元的部分按10%征收个人所得税．小明的妈妈月收入3500元，她每月要缴纳多少元个人所得税？
<gadget id="calculator">3_500 - 1_600</gadget>
<output>1_900</output>

<gadget id="calculator">1_900 - 500</gadget>
<output>1_400</output>

<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1_400 * (1/10)</gadget>
<output>140</output>

<gadget id="calculator">5 / 100</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">500 * (1/20)</gadget>
<output>25</output>

<gadget id="calculator">140 + 25</gadget>
<output>165</output>

<result>165</result>