You can do a lot with just two facts: - log 2 ~ 3/10 (which should be familiar to this audience) - log 3 ~ (19/12) log 2 ~ 19/40 (in musical terms this is the

You can do a lot with just two facts: - log 2 ~ 3/10 (which should be familiar to this audience) - log 3 ~ (19/12) log 2 ~ 19/40 (in musical terms this is the fact that seven semitones make a perfect fifth) - although arguably you don't even need this, since you can derive the same approximation by noting that log 8 ~ 9/10 and interpolating between log 8 and log 10.