1)5/12×4/1+7 = 5/3+7 = 7целых 5/3 = 8целых 2/3
2)4/9×3/4+2/3 = 1/3+2/3 = 3/3 = 1
3)2/5+1целая 1/4×1целая 3/5 = 2/5+5/4×8/5 = 2/5+2 = 2целые 2/5(×2) = 2целых4/10 = 2,4
4)2целых 3/10×2целых 1/2+1/2 = 23/10×5/2+1/2 = 23/4+1/2(×2) = 23/4+2/4 = 25/4 = 6целых 1/4(×25) = 6целых 25/100 = 6,25