Make estimates about different measurements for the same quantity based on the relative sizes of units. Learning targets: When students know a measurement in one unit, they can decide whether it takes more or less of a different unit to measure the same quantity. For the first activity, prepare to display or distribute 6-cm and 9-cm Cuisenaire rods, which are often colored dark green and blue, respectively. If Cuisenaire rods are not available, small and large paper clips can be substituted.