Add the fractions below using two methods:
1) the standard algorithm, and if possible,
2) by factoring the numerator and denominator to find the common denominator:
a) \(\Large \frac{3}{8}+\frac{1}{6}=\)
b) \(\Large \frac{2}{8}+\frac{5}{8}=\)
c) \(\Large \frac{3}{16}+\frac{4}{21}=\)
d) \(\Large \frac{1}{3}+\frac{1}{5}=\)