Final answer:
The step that creates separate models for different parts of a system is 'view modeling'. It allows for breaking down complex systems into manageable parts to understand and solve problems more effectively.
Step-by-step explanation:
The step that creates separate models for different parts of a system is known as view modeling. This process involves building individual models that represent various aspects or components of a larger system. It allows one to understand the world by breaking down complex systems into manageable parts which can then be examined and understood individually.
View modeling aligns with the concept that modeling replaces the real system by something similar but easier to examine. In doing so, it enables better insight and clearer focus on individual system components when trying to solve problems. Design a process through which these models can be integrated is the subsequent step following the development of these individual view models.
An example of a mathematical model would be a set of equations representing the economic market trends in different regions. However, here we're discussing view models specific to engineering, software design, or system analysis disciplines.