1)...= 25/4×7/5×8=5×7×2=70
2)...=27/8×1/2×16/9=6×1/2=3
3)...=3/4×5/4×15/2×9/4:15/2=3/4×5/4×15/2×9/4×2/15=15/16×9/4=135/64=2 целых 7/64.
4)...=15/16:49/48:15/7:100/49:24/145=15/16×48/49×7/15×49/100×145/24=45/49×7/15×49/20×29/24=3/7×49/20×29/24=21/20×29/24= 7/20×29/8 = 203/160=1 целая 43/160