Mathematics · 1st Year

Active learning ideas

Numbers 11-20: Teen Numbers

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.

• NCCA Curriculum Specifications
• NCCA: Primary - Number

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

Activity 01

• Placemat Activity
• 25 min · Small Groups

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.

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.

What to look for

Present students with numeral cards from 11-20. Ask them to hold up fingers to show the 'ones' group for each number. For example, for 17, they would hold up 7 fingers on one hand.

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

Activity 02

• Placemat Activity
• 20 min · Pairs

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.

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'.

What to look for

Give each student a small whiteboard. Write a teen number, such as 14. Ask them to draw a representation showing 'one ten' and 'four ones'. Collect and check for accurate grouping.

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

Activity 03

• Placemat Activity
• 30 min · Whole Class

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.

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.

What to look for

Ask students: 'How does knowing the number 10 help you understand the number 16?' Listen for explanations that include 'one group of ten and six more'.

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

Activity 04

• Placemat Activity
• 15 min · Pairs

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.

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.

What to look for

Present students with numeral cards from 11-20. Ask them to hold up fingers to show the 'ones' group for each number. For example, for 17, they would hold up 7 fingers on one hand.

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

A few notes on teaching this unit

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.

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.

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Watch Out for These Misconceptions

• During Manipulative Build: Teen Bundles, watch for students who count all items one-by-one without grouping ten as a unit.

  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.

• During Ten-Frame Fill: Number Matches, watch for students who treat the '1' in 13 as a single unit rather than a ten.

  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.'

• During Partner Trade: Ones to Tens, watch for students who reverse the structure and call fifteen 'five tens'.

  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.

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Methods used in this brief

• Placemat Activity