Find the sum and product of each of these pairs of numbers. Express your answers as a base 3 expansion

Find the sum and product of each of these pairs of numbers. Express your answers as a base 3 expansion.
a) (112)3, (210)3
b) (2112)3, (12021)3
c) (20001)3, (1111)3
d) (120021)3, (2002)3
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