On another weblog I got involved in a rather long-winded thread on colonialism in British India. Someone made an assertion about Islam and its relatively non-effect on the subcontinent. This seemed strange. My own family is brown and Muslim, but one can't generalize from one's own experience, no?
So I was bored, the combined population of India-Bangladesh-Pakistan ("British India") is 30.5% Muslim. Assuming 1% defection rates from a pure Hindu state toward a Muslim state per generation, how many generations would it take to reach 30.5%? Well, turns out it would take 37 generations, and assuming 25 years per generation,1, you have 925 years! Well, Muslims showed up as a force around 1000, so this is in the right ball park. Of course, there are simplifying assumptions here (discrete generations, constant rate of defection, etc.), but it gets the point across that elementary school math can elucidate in the blogosphere. I don't know what that says about the blogosphere, or, elementary school math.
1 - Some might object I would scale downward, but don't confuse pre-modern age of marriage with the customs in the age of relative plentitude.
Did you see this about baby and/or grown up math?