The division part of the arithmetic lesson is a bit out of order, the basic division lessons are immediately followed by 2-3 digit division with remainders.

EDIT

I have since then gotten to the fractions part, and for some of the practice lessons, there is an issue with the tool tip when simplifying fractions. When you click on the answer box, a popup appears saying to make your answer a proper or improper fraction, which was NOT what it wanted for an answer to one of the quiz questions. It happened for most of the questions where the answer could be a whole number. This is my most recent and frustrating encounter with this issue. I was taking the second quiz in the fractions area, when I came across this question, "Write 80/16 in simplest form" and when I clicked on the answer box it told me to write my answer as a proper or improper fraction, so I wrote 5/1, and it marked it as an incorrect answer. I opened the hints, and it told me that the answer was a whole 5, not 5/1 which was what the popup told me to write. I strongly feel that all of those types of questions need to either be all changed to accept proper-improper-mixed fractions, or it needs to be made significantly clearer which type of answer is needed for that question in particular.

It really isn't a great feeling having to retake a quiz because a tool tip was incorrect.