Montessori Tens Board | A Hands-On Math Activity for Learning Numbers 20–99

Learn how to use a Montessori Tens Board to teach numbers 20–99. Follow this simple, hands-on math lesson with golden bead bars and unit beads.

Traditional Montessori math materials help children understand abstract concepts through hands-on learning. Instead of memorizing numbers on a page, children can see, touch, count, and build quantities themselves. The Montessori Tens Board, also called Seguin Board B or Seguin Board 2, introduces children to the tens from 20 to 90 and helps them build numbers up to 99. Children combine golden ten-bars with individual unit beads. They then match these quantities to the corresponding written numerals. This simple presentation helps children understand place value. For example, the number 25 represents two tens and five units. Your child can physically build this quantity before connecting it to the written numeral. Montessori math follows a concrete-to-abstract approach. Children first explore quantities with their hands. They then connect these quantities to written symbols. This progression helps make early math more meaningful and prepares children for more advanced number work.

What Is the Purpose of the Montessori Tens Board?

The Montessori Tens Board helps children connect three important mathematical concepts:

• Quantity: The amount represented by a number, such as two ten-bars and five unit beads.
• Numeral: The written symbol, such as 25.
• Number composition: How tens and units combine to form a number.

For example, your child can build 25 using two ten-bars and five unit beads. This concrete experience shows that 25 contains two groups of ten and five additional units.

In Montessori math, I like to distinguish between what a number is and what a numeral says.

When your child holds five unit beads, you can say, “This is five.” When your child looks at the written numeral 5, you can say, “This says five.”

This simple distinction helps children connect the physical quantity with its written symbol.

The Tens Board also introduces number sequencing, counting by tens, and the relationship between tens and units. These skills prepare children for later work with place value and arithmetic.

At What Age Can You Introduce the Montessori Tens Board?

You can typically introduce the Tens Board during the preschool years, often around ages 4–5. However, age alone should not determine readiness.

Before introducing this material, your child will benefit from experience with counting, recognizing numerals, and working with the Montessori Teen Board. The Teen Board introduces numbers 11–19 and provides a foundation for understanding how tens and units combine.

Follow your child’s readiness rather than rushing through the lessons. Some children may be ready earlier, while others may need more time to explore smaller quantities.

Your goal is not to finish the entire board in one sitting. Your goal is to help your child understand the relationship between quantities and numerals.

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Montessori Tens Board Materials You Will Need:

Gather the following materials before beginning your Montessori math lesson:

• Montessori Tens Board
• Golden Bead Bars of 10
• Montessori Checker Board Beads
• Wooden numeral tiles for the unit digits 1–9, supplied with the board
• A floor mat or work mat
• Control of Error = there are a fixed amount of ten-bar beads

The golden bead bars represent groups of ten. Each individual bead represents one unit. The numeral tiles allow your child to build written numbers by combining the tens already shown on the board with the appropriate unit digit.

A note about the materials: The original presentation uses two Tens Boards and a supply of ten-bars. You can adapt the setup to the materials you have available. If you have only one board, introduce one tens sequence at a time.

How to Present the Montessori Tens Board:

Prepare the material before inviting your child to work. Arrange the boards on a floor mat or work surface. Place the numeral tiles, ten-bars, and unit beads nearby. Sit beside your child and demonstrate each step slowly. Use simple language. Allow your child to handle the materials and repeat the presentation independently when ready.

Step 1: Introduce the Tens

Begin with the written numeral 10.

Point to the numeral and say, “This says ten.” Then hold a golden ten-bar and say, “This is one ten.”

Place the ten-bar beside the numeral 10.

Begin with the written numeral 10.

Point to the numeral and say, “This says ten.” Then hold a golden ten-bar and say, “This is one ten.”

Place the ten-bar beside the numeral 10.

Next, point to 20 and say, “This says twenty.” Invite your child to bring you two ten-bars. Place them beside the numeral 20.

Continue with 30, 40, 50, and so on, up to 90. Match each numeral with the corresponding quantity of ten-bars.

Your child can help count the bars and place them beside each numeral.

This first step shows that each new group of ten contains one more ten-bar than the previous group.

• 10 = one ten-bar
• 20 = two ten-bars
• 30 = three ten-bars
• 40 = four ten-bars
• 50 = five ten-bars
• 60 = six ten-bars
• 70 = seven ten-bars
• 80 = eight ten-bars
• 90 = nine ten-bars

Allow your child to explore the quantities. There is no need to complete every number during the first presentation.

Step 2: Build Numbers Using Tens and Units

Once your child understands the tens, introduce the individual unit beads and numeral tiles.

Begin with 20. Point to the numeral and say, “This says twenty.” Show your child the two ten-bars that represent the quantity.

Now invite your child to build 25.

Start with the two ten-bars that represent 20. Then count out five individual unit beads. Place the five units beside the two ten-bars.

Point to the five unit beads and say, “This is five.”

Your child can now see that 25 contains two tens and five units.

Next, slide the numeral tile 5 into the unit position beside 20. The written numeral changes from 20 to 25.

Explain that the two tens remain the same. The unit digit changes the number.

Continue with other numbers, such as 21, 23, 26, and 29. You can then move to 31, 34, 47, or any other number your child is ready to build.

Offer the numbers in sequence at first. Later, invite your child to choose a numeral tile and build the matching quantity.

Important: When building 25, use two ten-bars and five unit beads. The quantity must match the numeral.

Step 3: Invite Your Child to Build Numbers Independently

After your demonstration, give your child time to explore the material.

Invite your child to choose a numeral tile. Encourage them to identify the tens already shown on the board and add the correct number of unit beads.

For example, to build 36, your child needs three ten-bars and six unit beads. The quantity represents 30 plus 6.

Ask simple, open-ended questions when appropriate:

• “How many tens do you see?”
• “How many units do we need?”
• “Can you show me another number that begins with three tens?”
• “What happens when we change the unit digit?”

Keep the experience playful and relaxed. Your child may want to build several numbers or repeat the same number multiple times. Repetition helps children become familiar with the material.

Step 4: Add Movement to the Math Lesson

Young children often benefit from opportunities to move during learning.

Place a few numeral tiles a short distance away from the work mat. Invite your child to walk over, select a tile, and bring it back to the board.

Your child can then build the corresponding quantity using ten-bars and unit beads.

You can also place the tiles in a small basket and invite your child to choose one at random.

This simple variation combines number recognition with movement, coordination, and independent decision-making.

Keep the movement purposeful and the workspace organized. If your child prefers to remain seated, allow that choice.

Why the Montessori Tens Board Works:

The Tens Board makes place value visible and tangible. Instead of treating 25 as a symbol to memorize, your child can build it using two ten-bars and five individual beads.

This hands-on process supports the Montessori principle of moving from concrete experiences toward abstract understanding. Montessori materials give children an opportunity to explore mathematical relationships through physical objects before relying on written numerals alone.

The material also gives children a clear way to compare quantities. Three ten-bars represent more than two ten-bars. Adding individual units changes the total without changing the number of tens. Over time, these experiences can help children build a stronger foundation for understanding place value and working with larger numbers.

Developmental Benefits:

Number Recognition and Number Association: Children connect written numerals with the quantities they represent. They learn that a numeral is more than a symbol on a page. It represents a specific amount.

Early Place-Value Understanding: The Tens Board shows how numbers consist of tens and units. Your child can see that 34 contains three tens and four units. This provides a foundation for understanding larger numbers.

Logical Thinking and Problem Solving: Building a number requires your child to identify the tens, count the units, and match the quantity to the correct numeral. Each step encourages careful observation and logical thinking.

Fine Motor Coordination: Picking up small beads, arranging ten-bars, and sliding numeral tiles into place gives your child opportunities to practice controlled hand movements. These actions also encourage hand-eye coordination.

Concentration and Independence: The orderly presentation encourages your child to focus on one task at a time. Once familiar with the material, your child can repeat the activity and check whether the quantities match the numerals.

Mathematical Knowledge: The lesson introduces useful vocabulary such as tens, units, quantity, and numeral. Consistent language helps your child describe what they see and build.

Can You Make a DIY Montessori Tens Board?

Yes! You can create a simple homemade version if you do not own the traditional wooden material. Use sturdy cardstock or cardboard to make a board with spaces for the tens numerals. You can use blue for tens and green for units to follow the color convention used in many Montessori math materials. Add removable numeral tiles for the unit digits. For the quantities, use ten-bead bars and individual beads, or make simple substitutes from craft materials.

For example, you can bundle ten craft sticks together to represent one ten. Use individual beads or counters to represent units. Make sure each ten-bar contains exactly ten items. Keep the materials organized so your child can count and compare quantities accurately. DIY materials do not need to look perfect. The most important feature is that your child can clearly distinguish a group of ten from a single unit.

Safety reminder: Small beads, pony beads, and other loose pieces can pose a choking hazard. Keep them away from children who still mouth objects, supervise the activity closely, and choose larger, age-appropriate counters when needed.

Montessori Tens Board Extensions:

Once your child feels comfortable building numbers, you can extend the lesson in several ways.

Use a Hundred Board:

A Montessori Hundred Board provides opportunities to explore number sequencing and patterns from 1 to 100. Invite your child to find a number they built on the Tens Board and locate it on the Hundred Board.

You can find more ideas in this Montessori Hundred Board activity.

Revisit the Montessori Teen Board:

The Teen Board introduces numbers 11–19. Revisiting this material helps reinforce the relationship between tens and units.

Read the related lesson: Working with Numerals and Beads: Teen Board Introduction.

Make Your Own Montessori Beads:

You can also create homemade bead bars using pipe cleaners and pony beads. This option works well when you want to explore Montessori math without purchasing a complete set of materials.

Follow the tutorial: DIY Montessori Checker Board Beads.

Explore Montessori Number Rods:

If your child is still developing an understanding of basic quantities, return to simpler materials before introducing larger numbers. Montessori Number Rods help children explore quantity and number sequence through graduated lengths.

Read more: Early Math with Number Rods and Sandpaper Numbers.

Tips for a Successful Montessori Math Lesson:

• Follow your child’s readiness. Introduce the material when your child shows interest and has a foundation in earlier number work.
• Demonstrate slowly. Show each step with a clear purpose. Avoid explaining too much at once.
• Use consistent language. Distinguish between the quantity a child builds and the numeral that represents it.
• Allow repetition. Your child may want to repeat the same numbers several times. Let them explore.
• Keep the lesson short. End the activity while your child remains engaged.
• Avoid turning the activity into a test. Offer invitations rather than quizzing your child repeatedly.
• Observe before correcting. Give your child time to notice a mismatch between the quantity and the numeral. Offer help when needed.
• Keep small materials safe. Choose age-appropriate pieces and supervise closely.

Remember that Montessori math is not about rushing a child toward advanced concepts. It is about building a meaningful understanding one step at a time.

Summary:

The Montessori Tens Board offers a hands-on way to introduce numbers 20–99. Children match written numerals with golden ten-bars and individual unit beads. Through this process, they begin to understand how tens and units combine to form larger numbers. You do not need to complete every number in one lesson. Start with a simple demonstration, allow your child to explore, and repeat the activity as interest grows. Above all, follow your child. When learning feels concrete, purposeful, and enjoyable, early math can become a natural part of your child’s Montessori journey.

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