This Instructional Activity is a part of the Lesson 2, Unit 3, Grade 6. The previous activity included only units of length, which are the most familiar to students since they started working with length in second grade and because rulers, yardsticks, and meter sticks are common classroom tools. This activity expands the list to include units of volume, weight, and mass. First, students categorize the units by the attribute they measure: length, volume, and weight or mass. Then they go through each type of unit, matching each provided benchmark object with the closest unit of measurement. Display several examples of real objects that are depicted on the cards, so the students can see them at actual size.