Kids who get screwed up on arithmetic will never learn more advanced topics, just as kids who don't learn to read (by non-use of phonics) will not likely gain much appreciation of literature.
Plus, in common usage, arithmetic is part of math.
Common people misunderstand lots of things and usually vote for Democrats.
When I went to school, the texts we used for the first six years were titled Growth in Arithmetic I-VI respectively
ML/NJ