18分之1+(3分之2+21分之4) = = = 是多少?

18分之1+(3分之2+21分之4) = = = 是多少?

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