Mathematics · Kindergarten

Active learning ideas

Teen Numbers: Ten and Some Ones

Teen numbers mix a familiar ten with a variable set of ones, a concept that challenges young learners to shift from seeing numbers as single units to understanding them as composed groups. Hands-on activities let students build, manipulate, and visually separate the ten from the ones, which turns an abstract idea into something they can touch and see.

• Common Core State Standards
• CCSS.Math.Content.K.NBT.A.1

• 15–30 min
• Pairs → Whole Class
• 3 activities

Activity 01

• Think-Pair-Share
• 15 min · Pairs

Think-Pair-Share: Build It Two Ways

Give each student 15 linking cubes. First ask them to show 15 any way they choose. Then ask: 'Can you show 15 as a group of ten and some ones?' Partners compare their structures and explain why both arrangements still show 15. Discuss how breaking it into a group of ten reveals the structure.

How does the number 10 help us understand numbers like 13 or 17?

Facilitation Tip

During Think-Pair-Share: Build It Two Ways, circulate and listen for students who describe the ten-group with language like ‘a stack’ or ‘a bundle’ rather than just ‘a one.’

What to look for

Give students a card with a teen number (e.g., 16). Ask them to draw a picture showing one group of ten and six ones, and to write a sentence explaining their drawing, like '16 is one ten and six ones.'

• Understand
• Apply
• Analyze
• Self-Awareness
• Relationship Skills

Activity 02

• Stations Rotation
• 30 min · Small Groups

Stations Rotation: Teen Number Lab

Stations include: bundle 10 craft sticks and add loose ones for a given teen number; fill a ten-frame completely and show extra ones beside it; and match a written teen numeral to a ten-and-ones drawing. Rotate every 8 minutes. Students record the equation (14 = 10 + 4) at each station.

Construct a model to show that 14 is a group of ten and four ones.

Facilitation Tip

In Teen Number Lab, insist on the same start for every station: students first build the full teen number with a ten-stick and loose cubes before writing any equation.

What to look for

Present students with a collection of 10 blocks and 5 loose blocks. Ask: 'How many blocks do you have in total?' Then ask: 'How many groups of ten do you have? How many ones do you have?'

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Activity 03

• Gallery Walk
• 30 min · Small Groups

Gallery Walk: Prove It Posters

Assign each small group a teen number. Groups create a poster showing: a bundle of ten plus loose ones, a filled ten-frame with extras, and the written equation (e.g., 14 = 10 + 4). Post around the room for a gallery walk where other groups leave one sticky-note observation on each poster.

Analyze why teen numbers are written with a '1' in the tens place.

Facilitation Tip

At Prove It Posters, ask students to hold up their ten-bundle when they explain the ‘1’ in their poster number to make the connection concrete.

What to look for

Show students the numeral '14'. Ask: 'What does the '1' in this number tell us? What does the '4' tell us? How do we know 14 is made of ten and four more?'

• Understand
• Apply
• Analyze
• Create
• Relationship Skills
• Social Awareness

A few notes on teaching this unit

Teach teen numbers by keeping the routine identical each time so students notice the pattern instead of treating each number as brand new. Use two-color tools so the ten-group stands out visually, and always bridge from the physical build to the written equation by pointing to each part while students hold the objects. Avoid rushing to symbolic notation before students can consistently explain the ten and the ones in their own words.

Students will confidently build teen numbers using a group of ten and some extra ones. They will explain the structure of each teen number both verbally and in writing, showing they see the ‘1’ as one group of ten and the second digit as the extra ones. By the end of these activities, they will write and read equations like 15 = 10 + 5 with clarity.

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Watch Out for These Misconceptions

• During Think-Pair-Share: Build It Two Ways, watch for students who build the ten but do not point to the digit ‘1’ when naming the group of ten.

  Prompt them to hold the ten-bundle while saying ‘one ten’ and then write the digit ‘1’ next to it on their paper, linking the bundle to the symbol.

• During Teen Number Lab, watch for students who treat each teen number as a separate fact rather than noticing the consistent ten plus some ones structure.

  Pause the station and have the whole group build 12, then 15, then 18 in sequence, asking what is the same and what is different so they see the repeated pattern.

• During Prove It Posters, watch for students who write the equation correctly but cannot explain what the ‘1’ represents when asked.

  Have them pick up their ten-bundle while saying ‘This is the ten the 1 stands for,’ then place it next to the ‘1’ in their poster to make the connection visible.

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Methods used in this brief

• Think-Pair-Share
• Stations Rotation
• Gallery Walk