The genotype of F1 individuals in a tetrahybrid cross is AaBbCcDd. Assuming independent assortment of these four genes, what are the probabilities

The genotype of F1 individuals in a tetrahybrid cross is AaBbCcDd.  Assuming independent assortment of these four genes, what are the probabilities that F2 offspring will have the following genotypes?a)aabbccddb)AaBbCcDdc)AABBCCDDd)AaBBCcDde)AaBBCCddPlease help me on tackling problems like this in a systematic way.