A simple activity that could be used for younger students and then adapted to make it more challenging for older students is discussing a sequence of steps in order to achieve something.
For example, for junior primary students the teacher could being by reading a book that explores the order students should brush their teeth, make a sandwich, or even grow a plant. Students could then work as a class to organise these steps on the board, allowing the activity to be interactive and fun for the students. This will help build sequencing skills and their development of ordinal numbers. As the students get older the activity could include arranging the sequence in the correct order and then complete the task, so each student could make a sandwich for lunch that day at school following the steps they set out.