1 out of 18 + (2 out of 3 + 4 out of 21) = = = How much is it?

1 out of 18 + (2 out of 3 + 4 out of 21) = = = How much is it?

1/18+(2/3+4/21)?
=1/18+(14/21+4/21)
=1/18+18/21
=1/18+6/7
=7/126+108/126
=115/126