help

[C# Programming]

Hello
can help me in my problem.I need deal with very big number to add,sub,multi and divide I can do the add,sub and multi but can't do the divide can help me.
I need divide very long integer number such that
x=444444444444444444444444444444444444444444444444444444444444444444444444
y=3333333333333333333333333333333333333333333333333333333

or more that each number consist from more of 300 digit can I divide it and result is div and mod.

thanks.