Two typists typed a thesis manuscript together, A typed 5/8 of the total number, B typed 20% of the total number, and they typed a total of 6699 words. How many words are there in this paper?
两个打字员合打一份论文稿，甲打了总数的(5/8)，乙打了总数的20%，两人共打了6699个字，这篇论文共有多少个字？
<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(5/8) + (1/5)</gadget>
<output>33/40 = around 0.825</output>

<gadget id="calculator">6_699 / (33/40)</gadget>
<output>8_120</output>

<result>8_120</result>