← Back to all activities한국어 → 📊 Data & probability

Change the rule,
and the groups change too

Early elementary · About 3 min read

A red triangle, a blue circle, a green square… the exact same objects can be grouped in completely different ways depending on what rule you choose.

🎮 Try the Sorting Things activity 📚 See other topics
🧑‍🤝‍🧑 Read this together with a grown-up. Some words may still be tricky to read alone. Reading it out loud together makes it easier to understand.

1Sorting means "gathering things that are alike"

Sorting is putting objects into groups based on some rule. Even putting dolls with dolls and blocks with blocks in a toy bin is a kind of sorting.

2There's more than one rule you can use

The same objects can be sorted by color, or by shape, or by size. Depending on which rule you pick, the groups end up completely different.

sorted by color (3 groups) sorted by shape (2 groups)
The exact same 6 objects — change the rule, and the way they group changes completely
There isn't just one right answer.
It's not that sorting by color is right and sorting by shape is wrong. Both are correct ways to sort — they just use a different rule.

3Pick just one rule at a time

When sorting, don't mix two rules together, like "color and shape at the same time" — use just one rule at a time. That way every object clearly belongs to exactly one group, with no confusion.

4Sorting makes counting easier

Once things are split into groups, it's much easier to count how many are in each group. This kind of sorting and counting is the foundation for graphs and tables you'll learn later.

5Try playing like this