Idea 3of 22Builds onEqual sections are equally likely
Probability as a fraction
How can a fraction say how likely something is?
Today you'll discover
- what goes on the bottom
- what goes on the top
- how to read the fraction
Think firstOne orange section out of four equal sections
What is the probability of landing on orange?
Decide first, then press Next. Count all the sections, then the ones you want.
A spinner of four equal sections, one orange and three blue, with a pointer. Numbers 1 to 4 appear round the rim; then the orange section is outlined; then the fraction 1/4 is written beside it. The last step shows six equal sections, two green.
See the whole ideathe big idea and the key word, in one place
The big idea
Probability is a fraction: the outcomes you want over all the equally likely outcomes.
Top over bottom
Count all the equal sections for the bottom, then the sections you want for the top.
- all sections4
- orange1
- probability1/4
Easy to get wrongThe bottom is every section, not just the others. 1 orange and 3 blue is 1/4, not 1/3.
Key word
- probability
- how likely an event is, written as a fraction from 0 to 1
Ready to use it?
- Write the probability of a colour on a spinner as a fraction.