Measuring things is not as easy as it looks. You have to make sure you start on the edge of the object or line. You can use anything to measure with, but you have to make sure it is end-to-end or the measurement will not be accurate. Grade 2 students must explore the use of non-standard measurements, so the Grade 3's get a little more practice.
Everyone likes to get a turn. We compare all the measurements and the tools. We talk about which tools are easier to use.