We describe chance with words: impossible, unlikely, even chance, likely, certain. Compare how many outcomes you want to how many there are altogether. If a bag is all red, drawing red is certain; if there is no red, it is impossible. When reds and blues are equal it is an even chance. More reds than blues makes red likely; fewer makes it unlikely. Count the actual objects, not the number of colours — three reds and one blue is not 50/50, because there are far more reds.
Explore this idea with maths tools
Maths you can move
Build 8 + 5
Tap two gold counters to fill the ten-frame.
8 in the frame + 5 waiting. The total stays the same.
Words to know
- likely
- more than an even chance of happening
- even chance
- equally likely to happen or not (50/50)
- certain
- sure to happen; impossible means it never can
Worked examples
Bag of only red counters — draw red?
- 1.Every counter is red.
- 2.So drawing red is certain.
= certain
3 red and 1 blue — draw red?
- 1.3 of the 4 counters are red.
- 2.More than half, so red is likely.
= likely
1 red and 3 blue — draw red?
- 1.Only 1 of 4 counters is red.
- 2.Fewer than half, so red is unlikely.
= unlikely
For parents
Method: Count the objects, then place the chance on the impossible-to-certain line.
What to say: Ask 'out of how many altogether?' — the total is every object, not just the ones you don't want.
Common mistakes:
- Thinking two colours means a 50/50 chance regardless of amounts.
- Giving the odds ('3 in 1') instead of the chance out of the total ('3 in 4').
- Treating '1 in 6' as a guarantee on the 6th try.