What is the definition of the slope?

For both the two main subjects I intend on teaching in this platform, I highly recommend to my students to focus on the theory as a first step (this could be a definition, some notes, etc). So, by trying to explain what the slope of a linear equation is we should start with the definition and see if the student understands every part of that definition. "The slope of a line is a number that measures its "steepness", usually denoted by the letter m. It is the change in y for a unit change in x along the line."Moreover, I have realised that several of my previous students understood concepts easier when they had a visual representation of what they were taught. I would present the formula that calculates the slope of a linear equation m = Δy / Δx and provide them with graphs that would show how the slope of the line can be represented visually.