2/9-1/6=
aducem fractiile la acelasi numitor
9=3²
6=2x3 calculam c.m.m.m.c
[9,6]=3²·2=18 deci numitorul comun este 18
18:9=2 deci cu 2 amplificam prima fractie
18:6=3 deci cu 3 amplificam a II fractie deci ex.devine
2/9-1/6=(2·2-1·3)/18=(4-3)/18=1/18
5/12-2/9=
12=2²·3
9=3²
[12,9]=2²·3²=4x9=36
ex.devine 5/12-2/9=(5·3-2·4)/36=(15-8)/36=7/36
