I learned to read at 4 years old, and I counted and even wrote crazy too before school. Parents were taught to work and motivated to gain knowledge. But the meaning? Those who knew nothing before school are taught this in the first classes, the difference in success soon is no longer visible, all students are drawn to the same level.
Our class, regardless of homework with parents, was steadily the first in the estimates and the Olympiads, there were no twins even among children from troubled families of the level of "Papa Alkas, Mom died, grandmother raises once a year". We had worthy teachers. They did not go online what stupid children went, they just taught, tried to interest, explained, and did not read the material at a distance. In our hometown, an orphan became the best student, her parents also taught at home, or is a good study the merit of teachers?