aducem fractiile la acelasi numitor, pt.aceasta calculam c.m.m.m.c.
5=5
4=2²
8=2³
[5,4,8]=2³x5=40
40:5=8 deci cu 8 amplificam pe 3/5
40:4=10 deci cu 10 amplificam pe 1/4
40:8=5 deci cu 5 amplificam pe 3/8
3/5-1/4+3/8=(3x8-1x10+3x5)/40=(24-10+15)/40=19/40
3/7-1/6+5/14=(3x6-1x7+5x3)/42=(18-7+15)/42=26/42=simplif=13/21
7/8-5/9-1/18=(7x9-5x8-1x4)/72=(63-40-4)/72=19/72
3/8-1/9=(3x9-1x8)/72=(27-8)/72=19/72
