This Fluency Activity is a part of the Lesson 23, Unit 4, Grade 1. Five options are provided in this lesson for the Core Fluency Practice Set, with Sheet A being the simplest addition fluency of the grade and Sheet E being the most complex. Start all students on Sheet A. Keeping a record of student progress is suggested to move students to more complex sheets as they are ready. Students complete as many problems as they can in 90 seconds.