Math in Focus

Well, after doing much researching on the internet, I decided to go with Math in Focus.  It's done by Houghton Mifflin but it is the Singapore Method. I really liked the look of the textbooks: very colorful, with lots of explanation and activities.  Each book has guided practice, practice, and tests.  Answers are in the back of the book.  I read that the teacher's manual isn't necessary.

The only catch is that it is quite expensive, but thanks to Ebay I got each book for around $10 to $15, which is great.  There are two textbooks per year and two workbooks per year, although I didn't see any workbooks for grades 6 and up.  There are extra practice books instead.  This curriculum is used in schools in the U.S. and it goes up to 8th grade.
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Another option I looked at was Primary Mathematics (Singapore Math) Standards edition.  The books have more practice and have a little more explanation than the U.S. edition.  It is slightly more expensive than the U.S. version but is less than Math in Focus.  However, it only goes to 6th grade, which is a disadvantage.