Frankly, the idea freaked me out. Why?
1. I didn't want my child(ren) to suffer unnecessarily.
2. I didn't want to look like a lame teacher.
Those are two of the big concerns that went through my head as I prepared to transition my children from homeschool to public school MATH.
In our case, one child went to public school kindergarten and then was homeschooled from 1st grade until the last couple months of 7th grade. Another child was entirely homeschooled--from kindergarten through the last couple months of 6th grade. So both were entering "middle school"-ish math classes, not having been in public school math for basically all of elementary school.
I didn't doubt that there would be holes in their learning. I think holes are pretty much inevitable when children only have one teacher...even when the teacher is a math genius...which I am not.
Someone recently posted a question on a math forum asking what to do to ensure that a child is at grade level and ready to transition from homeschool to public school. Here's a couple things to consider...
Check Out the Current Curriculum
One of the first things I did was ask to see what curriculum the school was using in my child's grade. However, it was important to also ask "how far have you gotten in the book this year?" It's not unusual for a class to not make it through an entire curriculum (or textbook) in a year. In one of my children's cases, I think the class had only made it a little over halfway through the book. If I would have assumed that the child had to know everything in the book, I might have panicked. (More than I was already!)
It's not a bad idea to ask to borrow a book for the summer prior to the child entering school. Although some schools may be reluctant, I think that most administrators would be happy to see that parents are interested in ensuring that a child is entering at grade level.
Look at NCTM's Focal Points/State Standards/Common Core Standards
National Council of Teacher's of Mathematics published "Focal Points" which specify what math content is to be covered at each grade level. Most states are aligning their standards with these Focal Points. Unfortunately, states aren't all interpreting the Focal Points the same way. So it's worthwhile to check your state standards to see what is expected for students in your state at each grade level. In June 2010, the National "Common Core State Standards" were released. This changes the playing field slightly, as each state considers how to implement. But if you look at the three--Focal Points, State Standards, Common Core Standards--you get a pretty good picture of what a child in a given grade level is expected to know.
The only other advice I have? Relax. I did not and I should have.
Yes, my children had a few holes. But for every hole, they were ahead in another area of math; they've spent more time waiting for the class to learn things that they already know than trying to catch up in things they were never taught. It all worked out.
The kids didn't suffer.
I didn't look too lame.