Funbrain has more than 40 interactive games to help students practice their decimal skills.  These activities include adding, subtracting, multiplying and dividing decimals.  You can select games of varying difficulty up to 4 decimal places.  There are also place value and rounding activities up to 7 decimal places.

On website, type “decimal” in Keyword box to see all of the game options. Best suited to grades 5-8.