general rule: multiply the denominators, and then multiply the numerators, then simplify.
Text p. 202
G - 4,5,6,8
B - 4,5,6,8,11
R - 4,5,6,811,15,17
Text p. 214-215
G - 1,2,6,9,
B - 1,2,6,9,11
R - 1,2,6,9,11,14,15
*Only draw diagrams if you are in blue or red groups!