How do you proove what the idempotents of the ring Z/100Z are?(adsbygoogle = window.adsbygoogle || []).push({});

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

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Idempotents of the ring Z/100Z

**Physics Forums | Science Articles, Homework Help, Discussion**