b. Calculate simple areas such as the area of a wall to buy tiles. [Einfache Flächen berechnen wie z.B. die Fläche einer Wand, um Fliesen zu kaufen.]

Nein

In terms of simple area calculation, e.g. the area of a wall to buy tiles, 15 test persons state that they can do this without any problems, four test persons are of the opinion that they can do this task with certain difficulties and one test person with great difficulties.

All test persons have a more or less comprehensive idea of what is meant by the term "simple surface". Apart from test person 12, who thinks of calculating the area of a circle, all test persons think of a rectangle when using this term or name the example wall. Furthermore, seven persons (TP 01, 04, 08, 10, 13, 15, 16) state that the term "simple surface" is used to connect a square and two test persons (TP 01, 04) triangles.

13 of the 15 test persons who state that they can easily calculate a simple area think of calculating a wall, i.e. a rectangle:

• "Length times width." (TP 02)
• "I also laid laminate myself in my apartment. You take length times width, how many square meters you need.” (TP 09)
• "I can definitely calculate the area of a wall. Length times width. A two-dimensional surface." (TP 16)
• "2.5 meters by 4 meters, that's relatively easy." (TP 19)

Test persons 08 and 11, who also report no problems with the calculation, think of somewhat more complex area calculations:

• "Multiply in your head, estimate and measure. That is no problem to calculate an area. Most of the time you have the formulas in your head and then you can easily calculate the area." (TP 08)
• "I have to know how many square meters. First in meters and then in square meters, then I have to add it up. Of course I can't calculate the number of plates, you have to tell the man where I buy [the plates].” (TP 11)

Of the five test persons who would have certain (TP 05, 06, 12, 17) or great (TP 03) difficulties with this task, four think of more extensive calculations of areas:

• "There I add up the 4 walls, so 3.5 x 4 m for wallpaper, for example." (TP 03)
• "Length times width would be easy, but as soon as a part has to be moved e.g. away from the heating, then I don't know how to subtract something from what." (TP 05)
• "Calculate a barrel or a circle." (TP 12)
• "I have the problem, I need the formula. There are people who can get it out of their heads, but I always need a formula." (TP 17)

Test person 06, who also has certain difficulties, however, thinks of simple calculations.

Again, the variance of the scale is largely due to the presumed complexity of the computational operations to be performed and not exclusively to the assessment of the underlying computational competence.

No changes recommended.

true