Number Sense
http://www.sheppardsoftware.com/mathgames/decimals/BalloonPopDecimals1.htm
Ordering Decimals Practice
www.abcya.com/place_value_hockey.htm
Place Value with decimals practice
Challenge Yourself: Each level you pass, try the next difficulty!
Ordering and Operations with Fractions and Decimals
Practice putting fractions and decimals in ordering from least to greatest, along with adding and subtracting fractions and decimals.
Go through each grade level mastering topics or jump to what you know you are having difficulty with and start from there.