Problem: The abacus was initially used for arithmetic tasks. The Roman abacus was used in Babylonia as early as 2400 BC. Since then, many other forms of reckoning boards or tables have been invented. In a medieval European counting house, a checkered cloth would be placed on a table, and markers moved around on it according to certain rules, as an aid to calculating sums of money.
A checkered cloth on a table was used in medieval Europe to help count what?
The answer is the following: sums of money


One of the earliest sexual orientation classification schemes was proposed in the 1860s by Karl Heinrich Ulrichs in a series of pamphlets he published privately. The classification scheme, which was meant only to describe males, separated them into three basic categories: dionings, urnings and uranodionings. An urning can be further categorized by degree of effeminacy. These categories directly correspond with the categories of sexual orientation used today: heterosexual, homosexual, and bisexual. In the series of pamphlets, Ulrichs outlined a set of questions to determine if a man was an urning. The definitions of each category of Ulrichs' classification scheme are as follows:
What did these three categories correspond with?
the categories of sexual orientation used today:


Input: Neolithic
In 1981 a team of researchers from the Maison de l'Orient et de la Méditerranée, including Jacques Cauvin and Oliver Aurenche divided Near East neolithic chronology into ten periods (0 to 9) based on social, economic and cultural characteristics. In 2002 Danielle Stordeur and Frédéric Abbès advanced this system with a division into five periods. Natufian (1) between 12,000 and 10,200 BC, Khiamian (2) between 10,200-8,800 BC, PPNA: Sultanian (Jericho), Mureybetian, early PPNB (PPNB ancien) (3) between 8,800-7,600 BC, middle PPNB (PPNB moyen) 7,600-6,900 BC, late PPNB (PPNB récent) (4) between 7,500 and 7,000 BC and a PPNB (sometimes called PPNC) transitional stage (PPNB final) (5) where Halaf and dark faced burnished ware begin to emerge between 6,900-6,400 BC. They also advanced the idea of a transitional stage between the PPNA and PPNB between 8,800 and 8,600 BC at sites like Jerf el Ahmar and Tell Aswad.

When was the original division of 10 advanced to a division of 5?
Output: 2002


Input: Article: The South American highlands were a center of early agriculture. Genetic testing of the wide variety of cultivars and wild species suggests that the potato has a single origin in the area of southern Peru, from a species in the Solanum brevicaule complex. Over 99% of all modern cultivated potatoes worldwide are descendants of a subspecies indigenous to south-central Chile, Solanum tuberosum ssp. tuberosum, where it was cultivated as long as 10,000 years ago. According to George Raudzens, "It is clear that in pre-Columbian times some groups struggled to survive and often suffered food shortages and famines, while others enjoyed a varied and substantial diet." The persistent drought around 850 AD coincided with the collapse of Classic Maya civilization, and the famine of One Rabbit (AD 1454) was a major catastrophe in Mexico.

Now answer this question: What event in 850 AD coincided with the collapse of Mayan civilization?

Output: persistent drought


Article: For much of Philadelphia's history, the typical home has been the row house. The row house was introduced to the United States via Philadelphia in the early 19th century and, for a time, row houses built elsewhere in the United States were known as "Philadelphia rows". A variety of row houses are found throughout the city, from Victorian-style homes in North Philadelphia to twin row houses in West Philadelphia. While newer homes are scattered throughout the city, much of the housing is from the early 20th century or older. The great age of the homes has created numerous problems, including blight and vacant lots in many parts of the city, while other neighborhoods such as Society Hill, which has the largest concentration of 18th-century architecture in the United States, have been rehabilitated and gentrified.

Question: Name a type of row house in the city?
Ans: Victorian-style homes in North Philadelphia to twin row houses in West Philadelphia


Input: Dissolution of the Soviet Union
On September 10, 1987, after a lecture from hardliner Yegor Ligachev at the Politburo for allowing these two unsanctioned demonstrations in Moscow, Boris Yeltsin wrote a letter of resignation to Gorbachev, who had been holidaying on the Black Sea. Gorbachev was stunned – no one had ever voluntarily resigned from the Politburo. At the October 27, 1987, plenary meeting of the Central Committee, Yeltsin, frustrated that Gorbachev had not addressed any of the issues outlined in his resignation letter, criticized the slow pace of reform, servility to the general secretary, and opposition from Ligachev that had led to his (Yeltsin's) resignation. No one had ever addressed the Party leader so brazenly in front of the Central Committee since Leon Trotsky in the 1920s. In his reply, Gorbachev accused Yeltsin of "political immaturity" and "absolute irresponsibility." No one backed Yeltsin.

Who disagreed vocally about the demonstrations being permitted?
Output:
Yegor Ligachev