bigger datatypes with struct

Hey,
for my project I have to use bigger datatypes than integer, long or long long!
I know the struct resources could help me there, but I also have to do some calculations with those numbers (multiply, modulo etc).
Does anyone know a libary, which can solve this problem?

Thanks for your help!

Does anyone know a libary, which can solve this problem?

What problem?

so my numbers have more than 30 digits and I have to do those math functions.
But the standard datatypes like long are just there for a maximum of 10 digits.
How can I implement big numbers like this?

So, you're saying "arduino big number" didn't turn anything up on Google?

sorry! I searched for everything, but I forgot about this. Thank you!