For sketching the graph of the modulus of f(x) (in graph transformations), why do we reflect in the x-axis anything that is below it?

Let's remember what applying a modulus to any number actually does. Applying the modulus to a number just gives us back the positive version of that number- if it is positive, we get back itself, and if it is negative, we get back the positive version of it. For example, the modulus of 5 is 5, and the modulus of -5 is 5 again.Let's see how this fits into our discussion of graphs. f(x) is a number after all for any specific fixed x- we plug in an x value and we get a number corresponding to that specific x value given by f(x) (i.e. its y-value). So let's say I take x=1. That will give me back f(1). If f(1) is positive, the point lies above the x-axis, since the y-value at x=1 is positive. Applying the modulus to f(1) will not change it- it will stay as it is, f(1). Hence if it is positive we leave the point as it is. So anything above the x-axis stays as it was before. Now, if f(1) happens to be negative, this means the y-value at x=1 is negative and the point lies below the x-axis. If we apply the modulus, we get the positive version of f(1), which is going to be that same y-value, but now becoming positive and so going above the x-axis. So for all points below the x-axis, we reflect them above the x-axis.Summarising, we have that points above the x-axis remain unchanged, whereas points below the x-axis get reflected in the x-axis upwards. Are we following, or do you need me to explain something again? [I would use a visual argument on the board as well, at the same time as explaining, so it can be clearer to the student.]