One thing I quickly noticed in France (and indeed anyone coming from a non-European country into continental Europe would notice) is that the school exercise books/notebooks were all gridded. It was impossible to find an A4 notebook that was simply ruled horizontally.
However, when I moved to Switzerland I discovered they were much easier to find. In fact, you can find both types easily.
... which begs the question: Why are notebooks in grid format instead of simply line ruled?
I couldn't really find a great deal of information. I found this post which wasn't exactly that helpful.
I found this too. Is it called a computation notebook?
A Computation notebook is a paper book that has special ruled lines of columns and rows for capturing information. This type of notebook has the appearance of graph paper and is typically used in engineering, math, and science.
The computation notebook is used in most colleges and universities in classes on multiple subjects. The format of this notebook makes delineation between topics easy to read and understand. Most math professors require their students to use a graphic format notebook to define math problems.
Many math algorithms and functions require a grid layout to plot the conditions or coordinates of an expression. A computation notebook includes a grid layout throughout the pages. This format provides a guide for documenting extensive mathematical problems. By using the grids as guidelines the problems are represented in clearly organized manner....Finally, what spurred this post.. watch this video at point 5:05 when this French girl talks about this very issue! The fact that UNgridded notebooks are so hard to find in France.
Btw I try to listen to random stuff on Youtube to improve my French listening comprehension. It's hard to find someone who is interesting to listen to and talks for a while on a topic that isn't too boring... well obviously her channel is about makeup... but she talks soooooo fast it sure is good practice! ;)
If anybody knows the answer, please leave a comment. Thanks! :)
A lined notebook - un cahier ligné
A grid notebook - un cahier carreaux
(image from here)