Description: The title gives the information that the number of chorus is 30% less than that of science and technology group, so it can be assumed that there are X people in science and technology group and x+ 14 people in chorus. At the same time, the title also tells us the sum of the two groups of people, so we can list an equation, solve the unknown x, and then calculate the total number of people in the two groups.
Expansion: This problem is a simple linear equation problem with one variable, which is a relatively basic content in junior high school mathematics. In the process of learning, we need to master the method of solving linear equations of one variable and how to list the equations according to the information in the topic. At the same time, we need to pay attention to the conversion of units to ensure the accuracy of the calculation results.