A website I found really useful when teaching about data and the representation was TopMarks. It gave you a whole load of different activities based on the idea of data, and data handling. The website gave you an opportunity to select the age group of said students. The url i decided to include was for the activity around bar charts. This activity gave you a lot of questions in terms of reading a bar charts data and giving the answer. The age group of the activity was 5-7 years. It seems to be a great introduction for children when deciphering data, and I think I would use something of its kind when I am teaching. https://mathsframe.co.uk/en/resources/resource/51/bar_charts