The numbers on the 100s chart are disappearing! Each day, provide the students with a mystery sheet, and see if they can figure out which numbers have disappeared! This is perfect for the 100th day of school, but it can also be used throughout the year. This set of 27 worksheets builds solid knowledge of how the 100s chart works. By the end of the unit, every learner should be able to complete a blank 100s chart. Use in a center or as a whole-class warm-up activity. Whether you use it for 100s day or as a daily warm-up, it is perfect for advanced kindergarten or all students in first or second grade. Developed by Alexandra Elliot, a K/1 teacher and special education teacher.