The error duplicates here. Copy my text below, and see if you can move the 2nd link up into the first paragraph.
Any (elementary) number theory, discrete math, or intro to proofs book will contain material on modular arithmetic. If you want to just learn modular arithmetic, I would go with sources on the web. Rutguers has an introduction, but there are
"In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..."
I get the same thing. Two links cannot be on same line.
Will have a look ... but until then just put extra links on new lines
"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman
I have also found a small irregularity:
When I try to enter this authors name, the name is on the top of this page:
the filter defeats me.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.