Aztec mathematics refers to the mathematical practices and concepts used by the Aztec civilization, which flourished in central Mexico from the 14th to the 16th centuries. The Aztecs had a sophisticated understanding of mathematics, which they used for practical purposes in areas like agriculture, trade, astronomy, and construction.

In mathematics, particularly in the study of reflection groups and Coxeter groups, a **Coxeter element** is a specific type of element that is associated with the generating reflections of a Coxeter group. More formally, a Coxeter group is defined by a set of generators that satisfy certain relations, typically corresponding to reflections across hyperplanes in a geometric space. A Coxeter element is typically constructed by taking a set of generators of the Coxeter group and forming their product in a specific order.

Nuclear technology in China encompasses various aspects including the development, construction, and operation of nuclear power plants, research in nuclear science, and advancements in nuclear technology applications. China has made significant investments in nuclear energy as part of its strategy to diversify its energy sources, reduce reliance on fossil fuels, and address climate change. Here are some key points related to nuclear technology in China: 1. **Nuclear Power Plants**: China has rapidly expanded its fleet of nuclear reactors.

Nuclear technology in Vietnam refers to the country's efforts to develop and utilize nuclear energy for various purposes, including electricity generation, medical applications, agricultural development, and scientific research. Vietnam's engagement with nuclear technology has evolved over the years, and while the country has made strides toward developing a nuclear power program, it has also emphasized safety, regulatory frameworks, and international cooperation.

Equivalent quantities refer to different measures or values that represent the same amount or concept in various forms. In different contexts, the term can have specific meanings: 1. **Mathematics**: In mathematics, equivalent quantities can refer to quantities that are equal to each other, such as fractions, percentages, or algebraic expressions. For example, \( \frac{1}{2} \) and \( 50\% \) are equivalent quantities since they represent the same portion of a whole.

Mechanical puzzles are physical puzzles that typically involve manipulating parts or components to achieve a specific goal or solve a problem. These puzzles often require reasoning, dexterity, and spatial awareness. They can take many forms, including: 1. **Disentanglement Puzzles**: These consist of several interlinked pieces that need to be separated. Examples include metal wire puzzles or string puzzles. 2. **Assembly Puzzles**: These require the assembly of various pieces into a complete shape or object.

Scale model collections refer to a hobby or practice where individuals create, collect, or display miniature representations of real-world objects, structures, vehicles, or figures. These models are usually crafted at a specific scale, meaning the model is a reduced-size version of the actual object.