Question

how will I add 2 5/12 + 1 2/3

Answer 1

You can add the natural numbers immediately, at which point you only need to add the fractions. You'll need a common denominator though!

Answer 2

make the denominator equal.
multply 12/3 with 4/4 it becomes 48/12
now add.
25/12 +48/12=
73/12