Idea 11of 22Builds onWhich spinner gives the better chance?
Same chance, different spinners
Can two different spinners give exactly the same chance?
Today you'll discover
- why more sections is not more chance
- how 2/4 and 4/8 match
- the same idea with marbles
Think firstSpinner B has more orange sections
Spinner B has more orange sections than A. Is orange more likely on B?
Decide first, then press Next. Compare each colour with the whole, not with the other spinner.
Two spinners side by side: spinner A of 4 equal sections, 2 orange; spinner B of 8, 4 orange. The sections are counted, then the fractions 2/4 and 4/8 are written under them, and the line under both says they are the same chance. The last step shows bag A, 1 orange marble of 3, beside bag B, 3 of 9.
See the whole ideathe big idea and the key word, in one place
The big idea
Equivalent fractions give the same chance, even when the spinners look different.
Same chance
Each pair names the same amount.
- 2 of 42/4
- 4 of 84/8
- half1/2
Easy to get wrongMore orange sections is only more likely if the share of the whole is bigger.
Key word
- equivalent fractions
- fractions that name the same amount, like 2/4, 4/8 and 1/2
Ready to use it?
- Decide whether two spinners or bags give the same chance.