Trihybrid Cross Fraction of Progeny! Help Please!?

I am asked to do a trihybrid cross branch diagram of a tall, purple flowered pea plant with round seeds TtPpRr ... with a tall, white flowered pea plant with wrinkled seeds Ttpprr.


So after I completed my diagram I get:
1/4 TT
1/2 Tt
1/4 tt

1/2 Pp
1/2 pp

1/2 Rr
1/2 rr


giving me the offspring and the fraction:
TTPpRr...............(1/4)(1/2)(1/2)= 1/16
TTPprr................(1/4)(1/2)(1/2)= 1/16
TTppRr...............(1/4)(1/2)(1/2)= 1/16
TTpprr................(1/4)(1/2)(1/2)= 1/16
TtPpRr................(1/2)(1/2)(1/2)= 1/8
TtPprr.................(1/2)(1/2)(1/2)= 1/8
TtppRr................(1/2)(1/2)(1/2)= 1/8
Ttpprr.................(1/2)(1/2)(1/2)= 1/8
ttPpRr................(1/4)(1/2)(1/2)= 1/16
ttPprr.................(1/4)(1/2)(1/2)= 1/16
ttppRr................(1/4)(1/2)(1/2)= 1/16
ttpprr.................(1/4)(1/2)(1/2)= 1/16



So the question is what is fraction of progeny?

I guess I'm confused because I don't know whether to add up the similar types and consider it some number out of 12 or if I simply times the fractions together of the like genotypes to get the fractions of 1/16 or 1/8...

So for:
tall purple and round I'll either have 2/12 or (1/16)(1/16)=(1/8) ... etc.
tall white and round
tall purple and wrinkled
tall white and wrinkled
short purple and round
short purple and wrinkled
short white and round
short white and wrinkled