Khan Academy
Khan Academy: Adding & Subtracting Decimals Word Problems
Practice solving word problems by adding or subtracting decimal numbers. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Homeschool Math
Homeschool Math: Adding and Subtracting Decimals (One Decimal Digit)
This is a complete lesson with instruction and a variety of exercises, teaching how to add and subtract decimals with one decimal digit (tenths).