Introduction to Probability: Likelihood of Events

Young learners build strong probability intuition through hands-on play with familiar objects before formal rules. Sorting games, spinners, and bag pulls turn abstract ideas like 'certain' or 'unlikely' into concrete experiences they can name, compare, and remember. Active learning connects new vocabulary directly to their daily observations, making the language of chance meaningful from the first lesson.

• Junior Infants
• Foundations of Mathematical Thinking
• 4 activities
• 20 min–35 min

Learning Objectives

1. Classify given events as impossible, unlikely, equally likely, likely, or certain.
2. Explain the reasoning used to determine if an event is impossible or certain.
3. Compare the likelihood of two different events using appropriate vocabulary.
4. Construct an example of an event that is unlikely but not impossible.

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⏱ 25 min·Small Groups

Sorting Game: Event Cards

Prepare picture cards showing events like 'it rains sweets' or 'the bell rings at break'. In small groups, children sort cards into five boxes labeled impossible, unlikely, equally likely, likely, certain. Groups share one example from each box with the class.

Prepare & details

Differentiate between impossible and certain events.

Facilitation Tip: During Sorting Game: Event Cards, circulate and ask each pair to explain why they placed a card in a particular category, listening for their use of evidence or prior knowledge.

Setup: Four corners of room clearly labeled, space to move

Materials: Corner labels (printed/projected), Discussion prompts

• Understand
• Analyze
• Evaluate
• Self-Awareness
• Social Awareness

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⏱ 30 min·Pairs

Bag Pulls: Color Chance

Fill bags with 10-20 colored pompoms, varying ratios like mostly blue for unlikely red. Pairs take turns predicting and pulling three times, recording with tallies or drawings. Discuss why some colors came up more.

Prepare & details

Explain how to determine if an event is equally likely to occur or not occur.

Facilitation Tip: During Bag Pulls: Color Chance, model how to record results in a simple tally chart so students see data collection as part of the process.

Setup: Four corners of room clearly labeled, space to move

Materials: Corner labels (printed/projected), Discussion prompts

• Understand
• Analyze
• Evaluate
• Self-Awareness
• Social Awareness

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⏱ 35 min·Whole Class

Spinner Trials: Prediction Wheel

Make large spinners with unequal sections for colors or faces. Whole class predicts likelihood before spinning 10 times as a group. Tally results on a chart and classify the spinner's outcomes together.

Prepare & details

Construct an example of an event that is unlikely but not impossible.

Facilitation Tip: During Spinner Trials: Prediction Wheel, have students sketch their spinner before spinning to connect their visual prediction with the actual outcome.

Setup: Four corners of room clearly labeled, space to move

Materials: Corner labels (printed/projected), Discussion prompts

• Understand
• Analyze
• Evaluate
• Self-Awareness
• Social Awareness

Four Corners

⏱ 20 min·Individual

Weather Chat: Daily Odds

Each morning, individuals draw weather pictures and label likelihood for rain or sun based on forecasts. Share in circle time, adjusting labels after observing the day. Track over a week on a class poster.

Prepare & details

Differentiate between impossible and certain events.

Facilitation Tip: During Weather Chat: Daily Odds, invite students to connect their personal routines to the chance language to deepen relevance.

Setup: Four corners of room clearly labeled, space to move

Materials: Corner labels (printed/projected), Discussion prompts

• Understand
• Analyze
• Evaluate
• Self-Awareness
• Social Awareness

Teaching This Topic

Experienced teachers begin with concrete objects students can manipulate, moving gradually toward language and symbols. They avoid rushing to definitions, instead letting students experience chance through repeated trials and compare predictions with results. Teachers listen closely during whole-group talks to catch early misconceptions and use peer explanations to correct them, trusting that repeated exposure builds lasting understanding.

What to Expect

By the end of these activities, students will confidently label events using the five likelihood words and explain their choices with evidence from trials. They will notice when outcomes are not equally likely and adjust predictions after gathering data, showing growing comfort with uncertainty. Whole-group sharing builds shared language and corrects individual missteps in real time.

Watch Out for These Misconceptions

Common Misconception

During Bag Pulls: Color Chance, watch for students who assume a single failed draw means an event can never happen.

What to Teach Instead

Pause the activity after a few pulls and ask the group to predict what might happen if they did 50 pulls instead of five. Record predictions, test again, and compare results to show unlikely events can still occur.

Common Misconception

During Spinner Trials: Prediction Wheel, watch for students who assume every spinner outcome is equally likely.

What to Teach Instead

Show students two different spinners side by side and ask them to estimate which one is more likely to land on red. Have them test both and tally results to see how unequal sections change likelihood.

Common Misconception

During Sorting Game: Event Cards, watch for students who label routines like school starting as uncertain after a single delay.

What to Teach Instead

Ask students to add five new routine cards to the 'certain' pile and justify each one. Include cards like 'School will start after a weekend' to highlight patterns that always happen.

Assessment Ideas

Exit Ticket

After Sorting Game: Event Cards, give each student a blank card. Ask them to write one event they know is certain and one they know is impossible, then draw a smiley face by the certain event and a neutral face by the impossible event.

Discussion Prompt

During Bag Pulls: Color Chance, present two bags of marbles and ask, 'Which bag makes drawing a red marble more likely?' Have students explain using the words likely, unlikely, or equally likely and point to the bag they chose.

Quick Check

During Weather Chat: Daily Odds, hold up picture cards showing events like a rainy day or a sunny day. Ask students to give a thumbs up for certain or likely, thumbs down for impossible or unlikely, and a sideways thumb for equally likely. Call on two students to justify their choices with evidence from the day's weather or prior activities.

Extensions & Scaffolding

• Challenge students to design their own spinner with three unequal sections and predict which outcome will happen most often before testing it 20 times.
• Scaffolding: Provide a word bank with the five likelihood words and sentence stems for students who need help articulating their reasoning during discussions.
• Deeper exploration: Introduce a second bag with mixed marbles and ask students to determine how many of each color would make two outcomes equally likely.

Key Vocabulary

Impossible	An event that cannot happen under any circumstances.
Unlikely	An event that has a small chance of happening.
Equally Likely	An event where two or more outcomes have the same chance of happening.
Likely	An event that has a good chance of happening.
Certain	An event that is guaranteed to happen.