Calculate 1 2/7 + 2 2/3. Give the answer as a mixed number in its simplest form

1 2/7 + 2 2/3 = 1 + 2 + 2/7 + 2/3

= 3 + 2/7 + 2/3
= 3 + 6/21 + 14/21
= 3 + 20/21
= 3 20/21

So, 1 2/7 + 2 2/3 = 3 20/21.