Jawabanmu

2014-02-27T22:05:04+07:00
(20/60+30/60+15/60+12/60) - (12/24+8/24+6/24) =
77/60 + 26/24 =
77/60 + 13/12 =
77/60 + 65/60 =
142/60 =
71/30