a) 3,45+ 4/3-1,25 = 3,45-1,25+4/3= 2,2 + 4/3 = 22/10 + 4/3 = 33/15 + 20/15 = 53/15
b) 17/3 - 11/5 + 5/3 = 17/3 + 5/3 - 11/5 = 22/3 - 11/5 = 110/15 - 33/15 = 77/15
c) 20/3 x 3/5 = 4 (bo skracasz 20 z 5 i 3 z 3 co daje 4 i 1)
d) 15/2 : 5/3 = 15/2 x 3/5 = 3/2 x 3 = 9/2 = 4 1/2
e) 5/6 x 7/1 x 30/7 = 5/6 x 30/1 (bo poskracaly sie 7) = 5 x 5 (bo skrocilo sie 6 i 30) = 25
