The best way to introduce decimals (likely to 4th graders) is to teach lessons that connect fractions to decimals. That's one of the reasons I like to immediately follow my fraction unit with my decimal unit.
Like fractions, decimals are a topic that needs to be taught for
Introducing Decimals
Like fractions, introducing decimals is something that should be taught for deep conceptual understanding in order for students to be successful in high level math classes. It can be easy, even tempting, to breeze through a decimal unit, but students need plenty of opportunities