Numbers 11-20: Teen NumbersActivities & Teaching Strategies
Active learning transforms teen numbers from abstract symbols into concrete quantities students can see, touch, and explain. Building with manipulatives and moving through structured activities turns counting into reasoning, which is essential for place value understanding in the teens.
Learning Objectives
- 1Identify the digit representing 'ten' and the digit representing 'ones' in teen numbers.
- 2Construct a visual representation of any teen number as a group of ten and a separate group of ones.
- 3Explain the additive relationship between 'ten' and the 'ones' digit to form a teen number.
- 4Compare the quantity represented by the digit 'one' with the quantity represented by the 'ones' digit in a teen number.
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Manipulative Build: Teen Bundles
Provide straws or linking cubes. Students first bundle 10 items into a ten-stick, then add 1-10 more loose items to make teen numbers. They label each bundle with a numeral card and share their models with the group.
Prepare & details
Differentiate between the number 'one' and the 'one' in 'thirteen'.
Facilitation Tip: During Manipulative Build: Teen Bundles, circulate to ensure students physically group ten items before adding the ones, reinforcing the ten-plus pattern.
Setup: Groups at tables with problem materials
Materials: Problem packet, Role cards (facilitator, recorder, timekeeper, reporter), Problem-solving protocol sheet, Solution evaluation rubric
Ten-Frame Fill: Number Matches
Print ten-frames and numeral cards 11-20. Students fill frames with counters to match each teen number, first filling the full ten then adding extras. Pairs check each other's work and record with drawings.
Prepare & details
Construct a model to show why 15 is 'ten and five'.
Facilitation Tip: In Ten-Frame Fill: Number Matches, ask students to explain their matches aloud to a partner, using the phrase 'one ten and ____ ones'.
Setup: Groups at tables with problem materials
Materials: Problem packet, Role cards (facilitator, recorder, timekeeper, reporter), Problem-solving protocol sheet, Solution evaluation rubric
Story Chain: Whole Class Relay
Teacher starts a story like 'I have 10 apples and get 4 more.' Students add manipulatives to show the teen total, say the number aloud, then continue the story. Rotate speakers around the circle.
Prepare & details
Explain how knowing about ten helps us understand numbers like sixteen.
Facilitation Tip: For Story Chain: Whole Class Relay, pause after each round to highlight how the decade structure (10, 11, 12...) supports quick counting.
Setup: Groups at tables with problem materials
Materials: Problem packet, Role cards (facilitator, recorder, timekeeper, reporter), Problem-solving protocol sheet, Solution evaluation rubric
Partner Trade: Ones to Tens
Pairs start with 15 loose counters. One student trades 10 for a ten-rod, then rebuilds to show the teen structure. Switch roles and discuss why grouping helps counting.
Prepare & details
Differentiate between the number 'one' and the 'one' in 'thirteen'.
Facilitation Tip: During Partner Trade: Ones to Tens, provide a visual anchor chart showing the exchange of ten ones for one ten-rod to guide partner discussions.
Setup: Groups at tables with problem materials
Materials: Problem packet, Role cards (facilitator, recorder, timekeeper, reporter), Problem-solving protocol sheet, Solution evaluation rubric
Teaching This Topic
Start with concrete materials like counters and ten-frames to build the ten-plus pattern, then connect these models to written numerals and spoken words. Avoid rushing to symbolic notation before students can explain the grouping in their own words. Research shows that students who verbalize their thinking while manipulating materials develop deeper place value understanding.
What to Expect
Students will confidently decompose teen numbers into 'one ten and some ones,' using models and language to explain their reasoning. They will recognize the decade structure and apply this understanding to counting and comparing numbers from 11 to 20.
These activities are a starting point. A full mission is the experience.
- Complete facilitation script with teacher dialogue
- Printable student materials, ready for class
- Differentiation strategies for every learner
Watch Out for These Misconceptions
Common MisconceptionDuring Manipulative Build: Teen Bundles, watch for students who count all items one-by-one without grouping ten as a unit.
What to Teach Instead
Prompt them to circle a group of ten first, then count the remaining ones, asking, 'How many full groups of ten do you see?' to redirect their focus.
Common MisconceptionDuring Ten-Frame Fill: Number Matches, watch for students who treat the '1' in 13 as a single unit rather than a ten.
What to Teach Instead
Have them place a ten-rod in the first frame and three counters in the second, then say, 'This is one ten and three ones, not thirteen separate ones.'
Common MisconceptionDuring Partner Trade: Ones to Tens, watch for students who reverse the structure and call fifteen 'five tens'.
What to Teach Instead
Ask them to rebuild fifteen with ten-rods and ones, then say the number aloud together as 'ten and five' to reinforce the correct structure.
Assessment Ideas
After Ten-Frame Fill: Number Matches, ask students to point to the 'ten' part and the 'ones' part in their matches and explain their choice to you as you circulate.
After Manipulative Build: Teen Bundles, give each student a numeral card (11-20) and ask them to build it using ten-rods and ones, then write the equation '10 + ___ = ___' on their whiteboard.
During Story Chain: Whole Class Relay, listen for students who use the phrase 'one ten and ____ ones' to describe their number, and highlight those explanations for the class.
Extensions & Scaffolding
- Challenge early finishers to create a mini-book where each page shows a teen number decomposed into tens and ones, with drawings and labels.
- Scaffolding for struggling students: Provide pre-grouped 'ten' sticks (e.g., bundled coffee stirrers) so they focus only on adding the ones.
- Deeper exploration: Introduce a 'missing ten' game where students roll a die to determine the 'ones' and must figure out what the 'ten' part is for numbers up to 20.
Key Vocabulary
| teen number | A number between 11 and 19 that is made up of one group of ten and some additional ones. |
| ten frame | A grid with two rows of five squares, used to visually represent numbers up to ten and to help understand place value. |
| ones group | The individual units or objects that are added to a group of ten to make a larger number. |
| place value | The value of a digit based on its position within a number; in teen numbers, the first digit represents tens and the second digit represents ones. |
Suggested Methodologies
Planning templates for Foundations of Mathematical Thinking
5E Model
The 5E Model structures lessons through five phases (Engage, Explore, Explain, Elaborate, and Evaluate), guiding students from curiosity to deep understanding through inquiry-based learning.
Unit PlannerMath Unit
Plan a multi-week math unit with conceptual coherence: from building number sense and procedural fluency to applying skills in context and developing mathematical reasoning across a connected sequence of lessons.
RubricMath Rubric
Build a math rubric that assesses problem-solving, mathematical reasoning, and communication alongside procedural accuracy, giving students feedback on how they think, not just whether they got the right answer.
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