54/55×24
=24*(1-1/55)
=24-24/55
=23又31/55
(4/9+7/3)×18×21
=18*21*4/9+18*21*7/3
=168+882
=1050
28/15×29
=2*29*(1-1/15)
=2*19-2*29/15
=58-58/15
=54又2/15
54/55×24
=24*(1-1/55)
=24-24/55
=23又31/55
(4/9+7/3)×18×21
=18*21*4/9+18*21*7/3
=168+882
=1050
28/15×29
=2*29*(1-1/15)
=2*19-2*29/15
=58-58/15
=54又2/15