[Ghost1716]

The question is :  If there are 3.33 × 10^20 atoms of nitrogen in (NH4)2C2O4,how much mg of (NH4)2C2O4 are there?
I would just like to know what I'm suppose to do to find it.I tried many times and i still couldn't find it.

[AWK]

This is exceptionally simple problem
atoms of N => moles of N => moles of oxalate => mass of oxalate
You need only look at molecular formula carefully and convert grams to miligrams.