This Fluency Activity is a part of the Lesson 12, Unit 3, Grade 5. This Sprint encourages students to strengthen their mental math strategies while subtracting fractions with unlike units. There are many ways to differentiate Sprints. Allow students to practice Sprints either at home or at school. Add a few seconds to Sprint B so students are sure to experience improvement. Encourage students who finish all problems before the time is up to list multiples of any given number on the back of their papers.