Detailed Instructions: 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.
Q: Passage: After establishing the Ming Dynasty, Zhu Yuanzhang began to consolidate the authority of the royal court. He assigned territories to the members of the royal family and stationed them across the empire. These members of the royal family did not have the administrative power over their territory, but they were entitled to a personal army that ranges from 3,000 to 19,000 men. Royal members that were stationed in the northern frontier were entitled to even larger forces. For instance, the Prince of Ning was said to have an army of over 80,000 men. The original crown prince Zhu Biao died at 36 in 1392, and his son Zhu Yunwen was made the crown prince. Zhu Yunwen was the nephew of the territorial princes, and he felt threatened by their military power. In May 1398, Zhu Yunwen ascended to the throne and became the Jianwen Emperor after the death of Zhu Yuanzhang. The princes were ordered to stay in their respective territories as the new emperor began planning for the reduction of their military power with his close associates Qi Tai and Huang Zicheng.
A:
How many years was Zhu Yunwen a crown prince?