Definition: 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.
Input: Passage: The Bechers had their first gallery exhibition in 1963 at the Galerie Ruth Nohl in Siegen. Their work became better known in the United States with the publication of their book Anonyme Skulpturen (Anonymous Sculptures) in 1970. The Bechers were shown at the George Eastman House and in solo exhibitions at Sonnabend Gallery, New York, in 1972. In 1974, the Institute of Contemporary Arts, London, organized an exhibition of their work, which toured the United Kingdom. The couple was invited to participate in Documenta 5, 6, 7, and 11 in Kassel in 1972, 1977, 1982 and 2002, and at the Bienal de Sao Paulo in 1977. The Van Abbemuseum, Eindhoven, organized a retrospective of the artists' work in 1981. In 1985 the artists had a major museum exhibition, which traveled to the Museum Folkwang, Essen, Musee d'Art Moderne de la Ville de Paris, and Musee d'Art Moderne de la Ville de Liege, Belgium. In 1991 the artists won the Leone d'Oro award for sculpture at the Venice Biennale. The Venice installation was reworked later in 1991, in a retrospective exhibition at the Kolnischer Kunstverein, Cologne. The Typologies installation was exhibited in 1994 at the Ydessa Hendeles Art Foundation, Toronto, and at the Westphalian State Museum of Art and Cultural History in Munster. Other retrospectives of the couple's work have been organized by the Photographische Sammlung/SK Stiftung Kulture in Cologne (1999 and 2003), Centre Georges Pompidou in Paris (2005) and Museum of Modern Art in New York (2008).
Output:
How many years was the couple invited to participate in Documenta?