This unit is the first of two related, companion units for grade 4. Muffles (of Muffles’ Truffles) returns, expands his business, and several problems arise as he tries to convert the measurements in his recipes to make bigger batches of truffles. Children are asked to select and use an appropriate measurement unit (U.S. Customary units), to compare and relate the measurements (length and liquid volume), to construct the need for decomposition of units into smaller units, and to use operations to convert within the system. The models used throughout are the double number line for equivalence and the ratio table for scaling and proportional reasoning.