How do you write a numerical or variable expression for each quantity: two dozen eggs?

The numerical expression for ##2## dozen eggs would be ##24## eggs. Because you already know that there are ##2## dozen eggs then you don't need a variable expression, as that is only needed if you don't know how many eggs you have. A variable expression would be used if the question was d dozen eggs.

d dozen eggs would equal to ##12d## as a variable expression because ##d## is the unknown.

I think this page might help if you are still confused. Numerical and variable expressions