Have you heard the research about the average young mathematician's inability to give an accurate measure of an object when it's moved to a spot on the ruler other than 0? The results are not so good and prove that the typical youngster doesn't understand a ruler and how to use it.
Donna from Math Coach's Corner has a great post about this concept and uses broken rulers to help remedy this measurement problem for kids. I combined her idea with a review concept I saw on Mrs. Daniel's blog Second Grace Sparkle to create the following activity.
I made the following four pages of broken ruler cards and cut them apart to create 24 individual cards.
If you're looking for a great math blog to follow, I'd recommend checking out Donna's. She knows what she's talking about!
FYI: This lesson was preceded by the creation of informal rulers, which definitely set them up to understand the above activity better. Go here if you'd like to know more.