Capacity (L, dL, mL)

L, dL and mL are met by counting containers and reading a scale. With 1 L = 10 dL and 1 dL = 100 mL, children restate a quantity in another unit, then add and subtract within one unit and across units, including the cases that carry and borrow.

The standard error is misremembering 1 L as 100 mL and writing 3 L as 300 mL, so an answer with one zero missing identifies it. In Measuring Capacity (Reading the Scale), children count the lines without checking whether one mark stands for 1 dL or 2 dL, and write half the real value.

Comparing Capacity judged more and less by pouring water between containers; here, the amount of water is written as a number of L, dL or mL. This numerical way of grasping quantity continues into Decimal Units (Capacity and Length) in grade 3, where compound units are rewritten as decimals.