Add these fractions (lowest terms)
a) 1/6 + 1/6 b) 1/4 + 3/8 c) 2/3 + 5/6
d) 9/21 + 4/7 e) 1 3/5 + 1/10
f) 1 1/4 + 11/12 g) 1 2/3 + 2/3
h) 1 5/6 + 3 2/5