> Had it been 105 year it would have been an order of magnitude

That’s not true. How are you getting that number? That’s not how you calculate an order of magnitude.

You don't “calculate” orders of magnitude, that the point of manipulating them in the first place. And an order of magnitude colloquially means “one more digit”, hence the original remark.

I appreciate the irony of nitpicking about a concept that merely exist to allow for low precision napkin math.

But in this case, the "napkin" math of 95 years would be off by 200 years! Hardly a useful estimate for this particular topic. Still confused where you come up with 105 years as an order of magnitude from 30.

> But in this case, the "napkin" math of 95 years would be off by 200 years!

Which is fine, because 300 and 100 are the same order of magnitude ;).

> Still confused where you come up with 105 years as an order of magnitude from 30.

30 ≈ 10^1

105 ≈ 10^2

Here you go.