One of the questions that I wrestled with in building this website was how to group and organize the topics. I ended up using grade level as the first sort.
Grade level can be a fairly arbitrary way of categorizing math topics. Standards vary from state to state. Implementation of the standards varies from within the state from school to school – and even in some cases from classroom to classroom. I grew up in Texas and currently live in Northern Virginia, so I rely largely on the standards published by the State of Virginia, augmented by materials from Texas and the National Council of Teachers of Mathematics
But more importantly – all kids absorb and internalize information at different rates. Indeed, that’s probably one of the reasons that parents visit a website like this one: they’re looking from material to reinforce the strengths and address those weaknesses that are unique to their kids.
So use the grade levels as a rough guideline – knowing that your particular state might be a bit different. The important thing to remember is that at home you can move forward at whatever rate is appropriate for your student,.