Montessori Mom

Sorting and Sizes

...s, s, s the sorting sound, S makes a super sorting sound!

Sorting is one of the most natural things children do. Watch a toddler with a pile of blocks and you will see them start grouping — all the red ones here, the big ones there. This impulse to organize is at the very heart of Montessori education. When we give children beautiful materials and a clear method for sorting by size, we are building the foundation for math, reading, and scientific thinking.

Why Sorting and Sizes Matter

Maria Montessori understood that children learn abstract concepts through concrete, hands-on experiences. Sorting objects from smallest to largest (or largest to smallest) teaches your child to observe carefully, compare, and make decisions. These are the same skills needed for counting, measuring, and even reading — where children must notice small differences between letters and words.

Sorting also builds vocabulary. Through these activities, your child will learn words like small, smaller, smallest, large, larger, largest, and medium. Use the three-period lesson to introduce these concepts: "This is the large one." Then: "Show me the large one." Finally: "Which one is this?"

Size Boards: Your First Sorting Lesson

Print the Size Board 1 and Size Cards 1. The board shows objects arranged from largest to smallest. The cards are individual pictures your child will match to the board.

How to present this lesson:

Place the board on a table or rug. Set the cards in a small pile or basket beside it. Pick up one card, look at it carefully, and slowly place it above (or below) the matching object on the board. Do this with slow, deliberate movements — your child is watching and learning from how you handle the materials. After placing two or three cards, invite your child to try.

When your child is comfortable with Size Board 1, introduce Size Board 2 and Size Cards 2 for a new set of objects to sort.

Making It More Challenging

Once your child can match cards to the board easily, try these extensions:

1. Remove the board entirely. Can your child arrange just the cards in order from largest to smallest?
2. Mix cards from both sets together and ask your child to sort them into two groups first, then arrange each group by size.
3. Introduce the words next largest and next smallest. Point to an object and ask: "Which one is the next smallest?"

Animal Sorting

Children love animals, and sorting animals by size is a wonderful way to combine nature study with math readiness. Print the Animal Board and Animal Cards. Your child will match beavers, tadpoles, and squirrels from largest to smallest.

For a second set, use the Seed Board and Seed Cards to sort acorns, corn, and maple seeds by size. This is a lovely way to talk about what you might find on a nature walk.

Tip: Laminate the boards and cards if you would like them to last. Cut carefully along the lines. You can store each set in a small envelope or zip bag so your child can choose which sorting work to do independently.

The Pink Tower Connection

If you have ever seen a Montessori classroom, you have probably noticed the Pink Tower — ten pink cubes ranging from very small to very large. It is one of the most iconic Montessori materials and it teaches exactly the same concept as our sorting printouts: grading by size.

You can bring this idea home without buying a Pink Tower. Gather ten objects of different sizes — blocks, boxes, cups, or stones — and invite your child to arrange them from smallest to largest. Start with just three objects for younger children and add more as they become confident.

Sorting Around the House

The kitchen is a wonderful sorting classroom. Try these activities with items you already have:

Measuring cups and spoons: Ask your child to nest them from smallest to largest. Can they find which one fits inside which?
Shoes: Line up family shoes from smallest (baby's) to largest (dad's). Count how many there are.
Fruit: Put a blueberry, a strawberry, an apple, and a grapefruit in a row from smallest to largest.
Nesting bowls or containers: Let your child stack them, nest them, and arrange them by size.

These everyday activities are just as valuable as printout work. Your child is learning that sorting and comparing happen everywhere — not just at a desk.

An Easy Lesson for Younger Children

For toddlers or children who are new to sorting, start with just two objects that are very different in size — a large ball and a small ball, or a big spoon and a little spoon. Use the three-period lesson:

"This is the big spoon." (Hold it up.)
"This is the small spoon." (Hold it up.)
"Can you give me the big spoon?"
"Can you give me the small spoon?"
"Which one is this?"

When your child is confident with two objects, add a third — the medium one. Three sizes are enough for most young children to begin with.

Sorting Art: Size Collage

Materials

Construction paper (one large sheet for the background)
Colored paper or old magazines
Scissors (child-safe)
Glue stick

Method

Cut out (or help your child cut out) circles in three sizes: small, medium, and large. Use the same color for all three so the focus is on size, not color. Glue them onto the background paper in order from smallest to largest, left to right. Your child can make several rows with different colors — a row of blue circles, a row of green circles, a row of red circles — each sorted by size.

For older children, try cutting out squares or triangles instead. Can they make a pattern that goes small, medium, large, small, medium, large? This is early pattern recognition — another important math skill.

Explore More Sorting Activities

Visit our Preschool Matching and Sorting Games page and our Sorting Printouts collection for even more free materials to use with your child.

Remember: Always adapt lessons for your child's needs. If a lesson feels too easy, add more objects or remove the control board. If it feels too hard, simplify — use fewer objects and bigger size differences. Follow your child's interest and pace. The goal is not perfection but joyful learning.

Recommended Materials

These hands-on materials pair beautifully with this lesson and our free printouts:

• Montessori Pink Tower — The classic Montessori sensorial material. Ten pink wooden cubes graduated from 1 cm to 10 cm, teaching size discrimination, visual perception, and concentration. The perfect companion to our size board printouts.
• Montessori Color and Shape Sorting Toy — 50 solid wood blocks in 5 colors and 5 shapes. Wonderful for combining color sorting with size grading, extending the activities in this lesson.
• Wooden Sorting and Stacking Toy — Educational shape sorting with color recognition. Designed for toddlers to explore sorting by color, shape, and size in a hands-on way.

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