Spanish and Catalan people often use technical words in school. I think the 'producte cartesià' is what my teachers called 'coordinates'. "Apparently they are called Cartesian because the idea was developed by the mathematician and philosopher Rene Descartes who was also known as Cartesius."

To explain Descartes' method, first think about using a street map. If you're trying to find a street that you've never been on before, you look for the street's name in the map's index. Suppose the index says that your target street is located at D12. This means that you go across the top of the map and find "D", and then you go down the side and find "12". You then trace down and across to find the box labelled as "D12", and look inside that box for the street you need. Somebody figured out that this was a handy way to specify the right general area on the map, telling you how far over (the D) and how far up or down (the 12) you needed to go. Descartes did something similar for mathematics.

http://www.purplemath.com/modules/plane.htm

http://jmathpage.com/JIMSGeometrycoordinates.html

I think in this case it's saying that the student can plot points on a plane. For example, it's possible to use pictures or syllables instead of numbers.



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Note added at 1 hr (2014-09-23 22:03:25 GMT)
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http://www.visualmathlearning.com/Exercises/Addition_Table_s...