Simple grammar workbook that really seems to get it across to my two sons is “Steck-Vaughn Core Skills Language Arts” published by Harcourt Achieve. ISBN 978-0-7398-7089-1 for the Grade 2 Volume.
The format is one topic per page with good, but not excessive practice of that topic. there is also a writing section in each book - how to construct sentences, paragraphs and book reports.
They have enjoyed it so far - and really retained the grammar skills they have studied. As a former English teacher, I am impressed at what hey have mastered so easily at their ages which are 8 and 9.
I bought the entire 8 book set three years ago, so I have no current prices or where to purchase, but if you type in the ISBN it should come up.
