Why should I learn mathematics ?

This is an interesting question: you get very different answers, if you ask a technician, a scientist, your uncle, your mother, or your teachers.
Anyway, it is a (questionable !) fact, that you must learn more or less mathematics in almost each education. In course for carpenters I gave the following answer to this question --- starting with a problem, a solution to the problem causing more detailed questions (typically ;-)) and ending up with some unexpected conclusions.

Given a wooden beam with a square cross-section of length q=20cm, take this beam (of sufficient length) to build a cube of side length s=100cm like that:
PICTURE exp_Why_I_cube.jpg
If you start cutting the edges for the cube, you will recognize, that not all of them need to be 100cm long. Some of the edges will be shorter because of the intersections at the corners of the cube. There are many possibilities to assemble the edges at the corners such that the side length of the cube is 100cm everywhere:
3 PICTURES exp_Why_I_cube_edges.jpg
After having built the cube, you can measure, how much of the length of the beam you actually needed (it is much less then 12m for the 12 edges, even forgetting the wood becoming sawdust -- we actually will neglect the wideness of the 12 cuts in the sequel for simplicity reasons !). As a human being, most likely, you will have estimated, or even calculated, the length of the beam you require in advance; in order to go sure for the outcome of your work before you waste your efforts.
Now I want to lure you into using ISAC you are visiting just now: Please, click one of the following calculations (even if you would build the cube in a another way):
calculate Fig.2 calculate Fig.3 calculate Fig.4