1995_Question_1

Screenshot 2020-07-08 at 15.04.07

To find all positive integers whose squares end in three 4’s :


Last line says : Consequently if N = 500k \pm 38, then {(N)}^2 ends in three 4s (Why)?

Can someone just explain to me this solution? I have no clue on how the HCF system works and how he got to that conclusion.

Thanks

Don’t know how to use latex so I wrote it up instead, hope this makes sense :slight_smile:

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:grin: