This Problem Set is a part of the Lesson 12, Unit 5, Grade 3. This lesson continues building understanding that comparisons of fractions are valid only when the two fractions refer to the same whole. Students work at stations to build a whole from various materials that represent a given fractional part. For example, given a piece of paper or length of string that represents 1/3, students assemble three copies of the item together to make 1 whole.