That is yet another difference, indeed: Primary school is only until grade 4 in most states, i.e. from around 6 to 10 years old. To be honest, I don't know if

That is yet another difference, indeed: Primary school is only until grade 4 in most states, i.e. from around 6 to 10 years old. To be honest, I don't know if and how much homework is assigned in primary school. I imagine that this also differs between states and even schools.