how to compare the large numbers without using calculator and/or without large calculation for the given two multiplication below, what is the relationship (>,< or =) .. between this two multiplication?
100210*90021 and 
100021*90210

I can simply compare these two results by calculation of multiplication but it is too time-consuming and not an effective way of solving this type of questions.
I want different way of finding the relationship (>,< or =) ..

Note that
$$100210 \cdot90021=(100021+189)(90210-189)=\\=100021\cdot90210+189\cdot 90220-189\cdot 100021$$ 
