The secretary prints a document, he typed 1600 words per hour, and finished (2/3) of the document after (5/4) hours, how many words are there in total?
秘书打印一份材料，他每小时打1600个字，(5/4)小时后完成这份材料的(2/3)，这份材料一共有多少个字？
<gadget id="calculator">5 / 4</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(5/4) / (2/3)</gadget>
<output>15/8 = around 1.875</output>

<gadget id="calculator">1_600 * (15/8)</gadget>
<output>3_000</output>

<result>3_000</result>