Lightning Talk: Quickly Estimating Powers-Of-Two in Your Head
summary
Shows a concrete mental method: split exponent into tens and ones, use 2^10 ≈ 1024 ≈ 10^3 to turn each ten into roughly 10^3, multiply by the small-power residue, and track the error which is about 2.5% per decade. Examples given and verified: 2^32 ≈ 4 billion, 2^23 ≈ 8 million, 2^36 ≈ 64 billion, 2^128 ≈ 2.5×10^38; method is simple arithmetic and yields correct orders of magnitude.
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chapters (4)
- 0:00Start
- 0:39The Small Powers of Two
- 1:10How I Calculate the Power of Nine in My Head
- 2:08Estimate the Larger Powers
