Adding & Subtracting Fractions with Uncommon Denominators

 $\frac{1}{4}+\frac{1}{2}$  

 $\frac{3}{8}+\frac{2}{4}$  

 $\frac{15}{16}-\frac{3}{4}$  

 $\frac{2}{12}+\frac{4}{6}$  

 $\frac{1}{2}+\frac{2}{10}$  

 $\frac{7}{9}-\frac{2}{3}$  

 $\frac{6}{15}-\frac{2}{5}$  

 $\frac{13}{20}-\frac{1}{4}$