In our country, ginger, brown sugar and water are often decocted and taken to prevent colds (commonly known as "ginger soup"). Ginger, brown sugar and water are generally prepared in a ratio of 2:5:75 and then boiled. Li Gang's mother is going to boil 1640 grams of "Ginger Soup", how many grams of brown sugar should be prepared? (Assuming that the loss in the process of boiling is not counted)
我国民间常用生姜、红糖和水煎服以防感冒(俗称"姜汤")，生姜、红糖和水一般按2：5：75的比例配好后煎熬．李刚的妈妈准备熬成1640克的"姜汤"，需准备红糖多少克？(假设熬的过程中损耗不计)
<gadget id="calculator">2 + 5 + 75</gadget>
<output>82</output>

<gadget id="calculator">5 / 82</gadget>
<output>5/82 = around 0.060976</output>

<gadget id="calculator">1_640 * (5/82)</gadget>
<output>100</output>

<result>100</result>