My students struggle with this concept year after year, but I finally found something that works! The students love it and their test scores show that they are finally grasping this concept!
This is a rounding strategy I created and use with my 2nd through 5th graders. Not only does it work on finding place value (by circling the place value), but also works on rounding (by looking at or underlining the neighbor)!
The students must determine if the neighbor is a nice guy, numbers 0-4, or a b