According to Baidu academic data, variation is a basic concept in mathematical application. Variant training can make students familiar with and master the operation law of variant and improve their mathematical application ability. The core concept of variant training is defined as: making effective changes from different angles, levels, situations and backgrounds, so that the conditions or forms change, but the essence remains unchanged.
The core concept is the center of a certain knowledge field, including basic concepts, basic laws and basic principles. These contents can show the picture of contemporary disciplines and are the backbone of the discipline structure. For example, several core concepts in mathematics, such as geometry, algebra and statistics, constitute the basic framework of mathematics.