Idea 12of 22Builds onProbability as a fraction
Predict how many times
How can a probability tell you what will happen in 20 spins?
Today you'll discover
- how to take a fraction of the spins
- why it says about
- how to use groups
Think firstA 1/4-orange spinner, spun 20 times
The spinner is 1/4 orange. In 20 spins, about how many will be orange?
Decide first, then press Next. Take the fraction of the number of spins.
A small spinner, one quarter orange, with the plan spin 20 times. The prediction appears: 1/4 of 20 = 5. Then 5 rows of 4 small circles, one filled in each row for orange. Then the tally of the real spins: 6 orange. The last step shows a 3/8-orange spinner spun 40 times.
See the whole ideathe big idea and the key word, in one place
The big idea
To predict, take the probability as a fraction of the spins: 1/4 of 20 is about 5.
Fraction of the spins
Divide by the bottom, then multiply by the top.
- spins40
- ÷ 85
- × 315
Easy to get wrongThe bottom of the fraction is not the answer. 1/4 of 20 spins is 5, not 4.
Key word
- prediction
- what you expect to happen, worked out before you try it
Ready to use it?
- Predict how many times a colour will come up in a number of spins.