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Australia
Year 3

15.01 Describe chance

Lesson

Are you ready?

Can you think of some words that describe the chance of something happening? What word would you use for the chance of winning the lottery? What word would you use to describe the chance of seeing a bird on the way to school?

Idea summary

Some words to describe the chance of something are: likely, unlikely, impossible and certain.

Likely or unlikely chance

Do you know how to describe how likely something is? This video will show you how.

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Examples

Example 1

The following fruit stickers are placed in a box. If Yuri reaches in without looking what is the chance that he selects a cherry sticker?

An image showing a lemon, a cherry and two bunches of grapes.
A
Unlikely
B
Likely
Worked Solution
Create a strategy

Count the number of cherry stickers.

Apply the idea

There is only 1 cherry sticker out of 4 stickers in the box. 1 out of 4 is small, so there is an unlikely chance that he will select a cherry sticker. The answer is option A.

Idea summary

Something is likely to happen if it will probably happen. Something is unlikely to happen if it will not probably happen.

Certain or impossible

How do we know if something is certain or impossible? Let's see here.

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Examples

Example 2

What is the chance my paper plane will fly forever?

A
Impossible
B
In between certain and impossible
C
Certain
Worked Solution
Create a strategy

Think about if a paper plane can fly forever.

Apply the idea

A paper plane must eventually land so it is impossible that it will fly forever. The answer is option A.

Idea summary

These are the 4 terms we have seen to describe chance:

  • Impossible: definitely will NOT happen.
  • Unlikely: more likely NOT to happen than to happen.
  • Likely: more likely to happen than not to happen.
  • Certain: definitely will happen.

Outcomes

ACMSP067

Conduct chance experiments, identify and describe possible outcomes and recognise variation in results

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