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## Main Question or Discussion Point

How do you proove what the idempotents of the ring Z/100Z are?

I know by trial and error that they are the elements 0,1,25,76 but have no proof as to why this is.

i know i have to find the integers 'a' such that 100 divides a(a-1)=a^2 -a but can do the maths to get a proper reasoning

any help?

thanks

I know by trial and error that they are the elements 0,1,25,76 but have no proof as to why this is.

i know i have to find the integers 'a' such that 100 divides a(a-1)=a^2 -a but can do the maths to get a proper reasoning

any help?

thanks