Totally agreed with you. I also taught 7-year old. Fewer than 10% of them would truly understand fraction means ratio. Heck, many of them had a hard time understanding what the word "ratio" means. Even fewer would understand what decimal numbers are or why they exist. I also saw how Russian School of Maths taught 7-year old. They would use an entire year in their honor class to introduce the concept of variable, first using analogies, then using terms like "rules", and eventually formalizing the concept.