A positive integer $k$ is called a 'lucky' number if the units digit of $k^4$ is 6. How many lucky numbers smaller than 1000 are there?

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A positive integer $k$ is called a "lucky" number if the units digit of $k^4$ is 6. How many lucky numbers smaller than 1000 are there?

Guest Aug 20, 2022

Guest · Answer 1 · 2022-08-21T01:18:52

listfor(k, 1, 5, k^4)==(1, 16, 81, 256, 625) ==Just 2 such "lucky" numbers: 16 and 256