calcule:

a)
[tex] \frac{1}{3} + \frac{5}{12} [/tex]
b)
[tex] \frac{1}{2} + \frac{3}{4} [/tex]
c)
[tex] \frac{2}{5} + \frac{1}{15} [/tex]

d)
[tex] \frac{1}{8} + \frac{3}{4} [/tex]