T

Chance: Possible, Likely & Certain

Maths · Y3 Chance
Year 3
Lesson Guide
Explanation
Chance has its own words, lined up from NO WAY to FOR SURE. IMPOSSIBLE things can never happen (a pig flying past your window). CERTAIN things must happen (the sun setting tonight). In between live UNLIKELY, EVEN CHANCE (a fair 50-50, like a coin flip) and LIKELY. Every event in the world has a home somewhere on this line.
Your Turn
Place these on the line: 'it will rain sometime this month', 'you will grow younger', 'a coin lands heads'. Check: likely, impossible, even chance.
Watch Out
Certain means MUST happen, no exceptions. 'My team will win' is likely at best — never certain!
Explanation
A fair coin has two sides and no favourites: heads and tails have exactly EVEN chance — 50-50. Here's the mind-bender: coins have no memory. Even after five heads in a row, the next flip is still 50-50! The coin doesn't know what happened before, and it isn't 'due' for tails. Each flip is a fresh start.
Your Turn
Flip a coin 10 times and tally H and T. Was it exactly 5-5? Close but not exact is completely normal!
Watch Out
The 'due' feeling is a famous trap — even adults fall for it. Fresh flip, fresh 50-50, every time.
Explanation
Spinners show chance with SPACE: the more of the circle a colour covers, the more likely the spinner lands there. This spinner is half green, quarter orange, quarter red — so green is most likely, and orange and red are equally likely as each other. Fractions and chance are teammates: the size of the share IS the chance!
Your Turn
Design a spinner where blue is CERTAIN. And one where blue is impossible. Check: all blue; and no blue at all!
Watch Out
Count SPACE, not sections. Two tiny red slivers still lose to one giant green half.
Explanation
A bag holds 5 green marbles and 1 red. Pull one out without looking: green is LIKELY (5 chances out of 6), red is UNLIKELY (1 out of 6). But listen: unlikely is NOT impossible — sometimes the red comes out! And likely is not certain — green usually wins, but not always. Counting the marbles tells you the chance; the pull still holds a surprise.
Your Turn
A bag has 3 blue, 3 yellow. What chance is blue? What about purple? Check: even chance (3 of 6); impossible (none in there!).
Watch Out
'Likely' promises nothing about ONE pull. It only means: over many pulls, green will show up most.
Explanation
You're a chance detective now! For any event, ask three questions: CAN it happen at all? (No → impossible.) MUST it happen? (Yes → certain.) Otherwise, how easily? — that places it at unlikely, even chance or likely. Rolling a 7 on a normal dice: impossible, sixes are the ceiling! Tomorrow having a morning: certain. Your teacher wearing blue this week: likely… but keep watch! Quiz and exercises to finish the whole Year 3 course — well done!
Your Turn
Make up one impossible, one certain and one even-chance event from your own day, and test them on someone at home.
Watch Out
Words like "probably" and "maybe" are chance words too — practise swapping them for the five proper terms.
Step 1: Introduction
Step 1 of 5
From NO WAY to FOR SURE impossible unlikely even chance likely certain can never happen must happen Impossible: a pig will fly past your window today. Certain: the sun will set tonight. Everything else lives somewhere in between!
Heads or tails? H T Two sides, both equally easy — a 50-50, EVEN chance. Neither side is 'due' — the coin has no memory! Five heads in a row? The next flip is STILL 50-50.
More space = more likely green ½ orange ¼ red ¼ Green covers HALF the spinner → green is most likely. Orange and red have equal quarter-shares — equally (un)likely.
Which colour will you pull out? 5 green 1 red Green is LIKELY (5 out of 6) — red is UNLIKELY (1 out of 6). But unlikely is NOT impossible — the red can still surprise you!
Chance detective 🎲 "Tomorrow will have a morning." CERTAIN — mornings never miss. "I will roll a 7 on one normal dice." IMPOSSIBLE — a dice only goes up to 6! "Our teacher will wear something blue this week." LIKELY — but watch and see! Ask: CAN it happen? MUST it happen? How easily? Quiz time!
Was this lesson helpful? Rate this Course
Discussion
Loading comments...