I had a young person ask me about modular arithmetic on calculators.

I have had very little dealings with modular arithmetic and i didn't think it was a function on most calculators.

I found this online modular calculator but I am confused about how it works.

you enter the mod you want (m)- that's easy enough

then you enter 2 numbers that you want to do arithmetic on. (a and b)

These numbers can contain digits greater than the mod so I assume they are base 10 numbers.

but this seems rather pointless and it isn't compatible with some of the outputs.

For instance it won't let you divide if the divisor is too big for the mod.

Modular Arithmetic Calculator

Can someone please explain what is happening to me? Is the calculator working as it should? Is there a better modular calculator on the web?

Thanks.