(1 3/5+1,8)×1/2= (2 1/3+0,25)×0,12= (1,25+1/6)×2,4=

(1 3/5+1,8)×1/2=
(1,6+1,8)×0,5=3,2×0,5=1,6

(2 1/3+0,25)×0,12=
(2 1/3+1/4)×12/100=
(2 4/12+3/12)×3/25=
26/12×3/25=26/100=0,26

(1,25+1/6)×2,4=
(1 1/4+1/6)×2 2/5=
(1 3/12+2/12)×12/5=
17/12×12/5=3 2/5=3,4