Area is taught in early grades. The concept of adding up all the square units that COVER a figure is actually pretty simple. Students need to understand WHAT area is before really delving into using the formulas and then taking them a step forward.
In secondary grades, we begin to use the formulas and study how areas of composite figures can be found as well as finding shaded areas. These types of problems bring in the “real-life” and “problem solving” component. I tell my students all the time, “You must know how to apply the problem and you must know how to think about it forwards and backwards.” (If you are given the sides, find the area. If you are given the area and one side, find the missing side.)
To take area a notch further, we throw in algebra. Instead of a side being just 4, we might make it 4x. We will talk about how area is quadratic, volume is cubic and perimeter is linear.
Before students get to pre-calculus, they also need to how dimensional changes affect the area. If all dimensions change, the area changes by that amount squared! So if all sides are doubled, then the new area will be quadrupled (or doubled squared). If one dimension changes, then the area is only affected by that amount!
I’ve been hard at work creating my Geometry Curriculum. My most recent resource covers area. The resource practices finding area of rectangles, parallelograms, squares, rhombi, triangles, and trapezoids. These figures are combined into composite figures and problems are worked forward and backwards. There is a special emphasis on regular polygons. Regular polygons are a great way to practice special right triangle rules and trig! There are tons of notes, practice and quizzes in this resource. If you need something like this, then go to my TpT store and check it out.