This is an activity to help support CCSS 2.MD.3 - Estimating lengths in centimeters, inches, feet, yards, meters, etc. In this activity, students choose 2 objects that are smaller than a ruler and estimate their lengths in inches and centimeters, then get their actual measurements. They also need to compare the difference between the estimated and actual measurements (intro to 2.MD.4).
There is a 2nd page that is done the same way, but they choose a larger object and estimate in feet and meters. My students always enjoy estimating and this activity lays it perfectly for them.
This could be used as an assessment too, if you want :)