Mathematics · Grade 3

Active learning ideas

Probability in Our World

Is it a good day for the park or should you bring an umbrella? This topic helps students become probability detectives, learning to use math to make smart predictions about the world around them.

• Ontario Curriculum Expectations
• Ontario Curriculum: Mathematics (2020) - Grade 3 - Strand D2: Probability

• 25–40 min
• Pairs → Whole Class
• 3 activities

Activity 01

• Think-Pair-Share
• 25 min · Pairs

Weather Reporter for a Day

Students examine real Canadian weather forecasts that use percentages for precipitation. They then translate these percentages into probability language, such as 'likely' or 'unlikely' to rain, and present their own 'forecast' to the class.

Explain how a weather forecast that says '80% chance of rain' uses the language of probability.

Facilitation Tip

Provide a visual scale or 'probability line' to help students connect percentages to descriptive words.

What to look for

Exit Ticket: Provide students with a list of three events (e.g., 'You will eat food today,' 'A cat will read a book,' 'You will roll a 4 on a die'). Ask them to label each as certain, impossible, or likely/unlikely and write one sentence explaining why.

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

Activity 02

• Think-Pair-Share
• 30 min · Small Groups

Mystery Bag Predictions

Place a mix of different coloured counters or blocks in an opaque bag (e.g., 7 red, 2 blue, 1 yellow). Students predict which colour is most likely and least likely to be pulled out, then conduct 10 trials, recording their results with tally marks.

Identify two games you play that involve chance and describe the likelihood of winning.

Facilitation Tip

After the experiment, reveal the bag's contents and lead a discussion comparing their results to what they might expect.

What to look for

Create-a-Game Project: Students design a simple game using a spinner they create. They must write a short set of rules and a paragraph explaining the likelihood of different outcomes in their game.

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

Activity 03

• Think-Pair-Share
• 40 min · Pairs

Design a Fair Spinner

In pairs, students are challenged to design and create a spinner for a game where two players have an equal chance of winning. They must be able to explain why their design is fair using the concept of 'equally likely'.

Analyse how understanding probability could help you make a better choice in a simple situation, like picking a team captain.

Facilitation Tip

Encourage students to think about the size and number of sections for each player on the spinner.

What to look for

Probability Reflection: After a coin-flipping experiment, students complete a worksheet with prompts like 'My prediction was...' and 'The actual result was...' and 'I think the results were different from my prediction because...'

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

A few notes on teaching this unit

Start with a whole-class discussion about the meaning of words like 'always,' 'sometimes,' and 'never.' Introduce a visual probability line on the board from 'Impossible' to 'Certain' and have students place event cards on it. Use hands-on tools before moving to abstract thought, allowing students to physically experience the results of their probability experiments.

Students will be able to describe the chance of everyday events using key vocabulary and test their predictions through fun, hands-on experiments with coins, dice, and spinners.

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Watch Out for These Misconceptions

• The Gambler's Fallacy: If a coin has landed on heads four times in a row, it is 'due' to land on tails next.

  Each coin flip is an independent event. The coin has no memory, so the probability of getting heads or tails is still 50/50 on every single flip, regardless of past results.

• All outcomes are equally likely: In a bag with 5 red marbles and 1 blue marble, pulling a blue one is just as likely as pulling a red one.

  The likelihood of an event depends on how many possible ways it can happen. Since there are more red marbles, you are more likely to pull a red one.

• Probability predicts the exact future: A 90% chance of rain means it will definitely rain today.

  Probability tells us what is likely to happen, but it's not a guarantee for a single event. It means that in 10 days with similar conditions, it would be expected to rain on 9 of them.

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Methods used in this brief

• Think-Pair-Share