Japan | A Nice Olympiads Trick | 3^12 - 81 | No Calculator Allowed

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[@manudude02]

Feels like this would almost be faster calculating it directly...
Got a link to the actual paper this was on?

[@russelleverson9915]

I was also wondering if direct calculation would be easier. Although, If all the x5 is too much, I'm also wondering is it any easier to start with the highest power of five that I can confidently remember. (In my case, 5⁴ = 625), then add a 0 and divide the result by 2, to get 5⁵, then continue to repeatedly add a zero and divide by 2, until I get to 5¹¹ 🤔

[@manudude02]

@@russelleverson9915 that would be what I would do, or just calculate 10^11/2^11

[@russelleverson9915]

@@manudude02 I thought about that as well, But I assumed that I wouldn't be allowed to use a calculator and... I didn't fancy dividing anything by 2¹¹ (=2048?) using pen and paper. 😳

[@manudude02]

@@russelleverson9915 2048 is close enough to 2000 that it wouldn't be too bad.