Last night we talked about writing in base 3. A long long long time ago we talked about writing 1/3 in binary. Here are those two projects:
I suspected that the boys wouldn’t remember the project about writing 1/3 in binary, so I thought it would make a good follow up to last night’s project.
I started by just posing the question and seeing where things went. They boys had lots of ideas and we eventually got most of the way there:
At the end of the last video they boys figured out that if our number was indeed 1/3, if we multiplied it by 3 we should get 1. That reminded them of the proof that 0.9999…. (repeating forever) = 1.
We reviewed that proof and applied it to the situation we had now.
Just one little problem . . . what if we apply the idea in this proof to a different series, say 1 + 2 + 4 + 8 + 16 + . . . . ?
We’ve looked at the idea in this video before:
Jordan Ellenberg’s “Algebraic Intimidation”
We felt pretty comfortable believing that 0.9999…. = 1 and that we’d found the correct series for 1/3 in binary, but do we believe the results when we apply the exact same ideas to a new series?
I love projects like this one 🙂