This holiday was started in 1979 by a teacher, Lynn Taylor. Her idea was to help children understand the lesson of the number 100. Today, it is a large part of classroom culture and symbolizes a celebration of your student's achievements for the school year in a fun way. The event focuses on the number 100 and helps develop a child's number sense and math skills for numbers up to 100. Beyond the math activities, there are 100th day activities like performing acts of kindness, making a 100th day of school shirt , writing prompts, and hands-on activities that all relate to the number 100.