(3) (1)/(8)+(7)/(12)= (4) (5)/(8)+(5)/(12)= (5) (3)/(7)+(1)/(14)= (6) (3)/(7)+(5)/(14)=

(3) $\frac {1}{8}+\frac {7}{12}=\frac {3}{24}+\frac {14}{24}=\frac {17}{24}$<br /><br />(4) $\frac {5}{8}+\frac {5}{12}=\frac {15}{24}+\frac {10}{24}=\frac {25}{245) $\frac {3}{7}+\frac {1}{14}=\frac {6}{14}+\frac {1}{14}=\frac {7}{14}$<br /><br />(6) $\frac {3}{7}+\frac {5}{14}=\frac {6}{14}+\frac {5}{14}=\frac {11}{14}$