Grade 5

Ask students what they can say and cannot say about the marbles in the bag and how much certainty they can say it with.

April’s friend put marbles of three different colors in the bag without letting April know what colors or how many of each. April then took one marble out of the bag, recorded its color, and put it back. She repeated this activity several times. One third of the marbles she took out were red.

- We don’t know how many pulls she took, but it must have been a multiple of 3— she might have seen 2 reds out of 6 pulls.
- We don’t know what the other two colors are or in what fraction of pulls they appeared.
- We don’t know how many marbles are in the bag.
- We do know for sure that there is at least one red marble in the bag. It is possible that there is exactly one red marble and that April just happened to pull it out quite frequently.

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