Răspuns :
5/12+7/15-3/20=
12=2²•3
15=5•3
20=2²•5•3
----------------
2²•3•5=60(numitorul comun)
5/12=25/60
7/15=28/60
3/20=9/60
(25+28-9)/60=(53-9)/60=44/60=22/30=11/15
5/12 + 7/15 - 3/20 =
25/60 + 28/60 - 9/60 =
53/60 - 9/60
44/60 = 22/30 = 11/15
25/60 + 28/60 - 9/60 =
53/60 - 9/60
44/60 = 22/30 = 11/15