How to teach sorting and counting data

Pre-K to Grade 1

Early data work is the first taste of statistics: sort objects into groups by a feature (colour, shape, type), count how many are in each group, and compare the groups (which has most, which has least, how many more). It is often shown as a simple picture graph with one picture per item.

How to teach it

1. Start by sorting real objects into clear categories, agreeing the sorting rule before counting.
2. Count each group carefully and record the number, one count per category.
3. Build a picture graph with one picture standing for one item, lined up so columns can be compared by height.
4. Ask and answer the key questions: which group has the most, which the least, and how many more one has than another.
5. Connect 'how many more' to subtraction by comparing the two counts.

Common mistakes

• Overlapping categories so an object could belong to two groups.
• Miscounting a group, or counting one item in two categories.
• Not lining up the pictures, so a taller-looking column actually has fewer.
• Answering 'how many more' by reading one column instead of comparing the two.