Mentally computing 3rd and 5th roots

A couple years ago I wrote about a trick for mentally computing the fifth root of an integer if you know that the number you’re starting with is the fifth power of a two-digit number.

This morning I wrote up a similar (and simpler) trick for cube roots as a thread on @AlgebraFact. You can find the Twitter thread starting here, or you could go to this page that unrolls the whole thread in one page.

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