1)15целых 2/5-1целая 1/24+6 2)28целых-24целых1/7+4целых1/5 3)1целая-1/16-1/32+1/2 4)21целая-(4целых1/8-2целых1/4

15 2/5-1 1/24+6=
=21 2/5-1 1/24=21 36/120-1 5/120=
=20 31/120

27-24 1/7+4 1/5=2 6/7+4 1/5=
=2 30/35+4 7/35=6 37/35=7 2/35

1 -1/16-1/32+1/2=
=15/16-1/32+1/2=
=30/32-1/32+16/32=45/32=1 13/32

21-(4 1/8-2 1/4)=21-(4 1/8-2 2/8)=
=21-(3 9/8-2 2/8)=21-1 7/8=
=20 8/8-1 7/8=19 1/8