Given the task definition and input, reply with output. This task involves creating questions from a given passage that involve some kind of complex reasoning (including numerical reasoning).
The generated questions must require looking at more than one part of the passage to answer. Try to use a variety of reasoning types in your questions (some of the sample reasoning types are illustrated in the 'positive examples' field) and also have a variety of answer types (spans, numbers, dates). A span is a continuous phrase taken directly from the passage or question. In such questions, the answer spans are recommended to be five words. Questions with answer type "number", are expected to start with "How many". For instance, "How long did an event last?" can be phrased as "How many years did an event last?". To increase diversity, try to create more questions for which the answer will be multiple spans. Please create questions that require AT LEAST 2 arithmetic operations as illustrated in the 'positive examples' field. You are encouraged to try DIFFERENT COMBINATIONS of operations and not just limit to the combinations shown in those examples. The more challenging questions you create, the better it is.

Passage: By the end of 1986, Computer Entertainer claimed the Atari 7800 had sold 100,000 consoles in the United States, less than the Sega Master Systems 125,000 and the Nintendo Entertainment Systems 1.1 million. According to Atari, due to manufacturing problems, it only managed to produce and sell 100,000 units by 1986, including units that had been in a warehouse since 1984. A common complaint in 1986 was a lack of games, including a gap of months between new releases (Galagas release in August was followed by Xevious in November). By the end of 1986, the 7800 had 10 games, compared to Segas 20 and Nintendos 36; nine of the NES games were third-party, whereas the 7800 and Master System had no third-party games. A reason cited for the lack of third-party interest in the 7800 was its small 100,000 install base and low market penetration.
How many months passed between the release of Galagas and Xevious?