Sorting Objects by Color, Size, and Shape - First Grade Mathematics

Have you ever dumped a giant bin of colorful building bricks onto the rug and wondered how to find the exact piece you need? When items are mixed together in a messy pile, finding information is difficult. That is why mathematicians sort! Sorting means organizing a collection of objects into separate groups based on a shared rule or feature called an attribute. In first grade, you will learn how to sort collections by three of the most powerful attributes: color, size, and shape. In this chapter, you will master the art of sorting by one attribute and learn how to count and compare the groups you create.

What Is an Attribute?

An attribute is a characteristic or quality that describes an object, such as its color, its shape, its size, or its texture.

The Three Big Sorting Attributes:
1. COLOR: Red, Blue, Yellow, Green, Orange, Purple.
2. SHAPE: Circles, Squares, Triangles, Hexagons.
3. SIZE:  Big (Large), Medium, Small (Tiny).

Choosing One Sorting Rule

When sorting by one attribute, you pick ONE rule and stick to it strictly! If your rule is "Sort by Color," you only look at colors (all red objects go in one pile, all blue objects go in another), ignoring their shapes and sizes. If your rule is "Sort by Shape," all triangles go together, regardless of whether they are red, blue, big, or small!

Example 1: Sorting by Color

Imagine a collection of buttons: some red, some blue, and some yellow.

Sorting Buttons by Color:
Messy Mixed Pile:
  (Red Circle)    [Blue Square]    (Yellow Circle)    (Red Triangle)
  [Blue Triangle] (Yellow Square)  (Red Square)       [Blue Circle]

Sorted into Color Groups:
Red Group:    (Red Circle)   (Red Triangle)   (Red Square)    -> 3 Red items
Blue Group:   [Blue Square]  [Blue Triangle]  [Blue Circle]   -> 3 Blue items
Yellow Group: (Yellow Circle)(Yellow Square)                  -> 2 Yellow items

Counting and Comparing the Groups

Once sorted by color, you can easily count the groups: 3 Red, 3 Blue, and 2 Yellow. You can immediately see that Yellow has the fewest buttons!

Example 2: Sorting by Shape

Now take the exact same collection of buttons and sort them by a different rule: SHAPE!

Sorting the Same Buttons by Shape:
Circles Group:   (Red Circle)    (Yellow Circle)  [Blue Circle]    -> 3 Circles
Squares Group:   [Blue Square]   (Yellow Square)  (Red Square)     -> 3 Squares
Triangles Group: (Red Triangle)  [Blue Triangle]                   -> 2 Triangles

Notice the Magic of Sorting!

The exact same objects can be sorted in completely different ways depending on which attribute rule you choose! When sorted by color, there were 3 groups. When sorted by shape, there were also 3 groups, but the items in each pile changed.

Example 3: Sorting by Size

You can also sort objects into two simple piles: Big and Small!

Sorting by Size:
Big Group:    [ Big Bear ]    ( Big Ball )    + Big Block +
Small Group:  [ Small Bear ]  ( Small Ball )  + Small Block +

Practice Exercises

Exercise 1: What is an attribute in mathematics? Name three common attributes used to sort objects.

Exercise 2: You have a box of crayons with 4 red crayons, 6 blue crayons, and 3 green crayons. What attribute did you use to sort them, and which group has the most crayons?

Exercise 3: You have a pile of shapes containing 5 circles, 8 triangles, and 2 squares. Which shape group has the least number of items?

Exercise 4: Can the exact same group of toys be sorted by color first, and then sorted by size? Explain why.

Solutions and Explanations

Solution to Exercise 1: An attribute is a descriptive feature or characteristic of an object. Three common attributes used for sorting are color, shape, and size.

Solution to Exercise 2: You sorted the crayons by the attribute of color. The blue group has the most crayons (6 crayons).

Solution to Exercise 3: The squares group has the least number of items (only 2 squares).

Solution to Exercise 4: Yes, the exact same group of toys can be sorted in multiple ways. First, you could group all red toys together and all blue toys together. Then you could scramble them and regroup them by putting all big toys together and all small toys together. The sorting rule you choose determines how the groups are formed.