19.2*135-144/1000*1920+209*123/125
=19.2*135-14.4*19.2+209*(1-2/125)
=19.2*(135-14.4)+209-418/125
=(20-0.8)*120.6+209-418*8/1000
=2412-96.48+209-3.344
=2621-99.824
=2521.176
1/1*3+1/3*5+1/5*7+.+1/97*99
=[(1-1/3)+(1/3-1/5)+(1/5-1/7)+.+(1/97-1/99)]÷2
=(1-1/99)÷2
=49/99
1/8128+1/254+1/508+1/1016+1/2032+1/4064+1/8128
=1/8128+1/8128+1/4064+1/2032+1/1016+1/508+1/254
=1/4064+1/4064+1/2032+1/1016+1/508+1/254
=1/2032+1/2032+1/1016+1/508+1/254
=1/1016+1/1016+1/508+1/254
=1/508+1/508+1/254
=1/254+1/254
=1/127
44/45*37-8/45
=4/45*(11*37-2)
=4/45*(407-2)
=4/45*405
=36
3/4*17+0.25*29
=1/4*(3*17+29)
=1/4*(51+29)
=1/4*80
=20
12/13/(53.9*2/3)
=
2.6/[(7/12-5/16)*1.6]
=2.6/[7*1.6/12-5*1.6/16]
=2.6/[28/30-1/2]
=2.6*30/13
=6 19.2*135-144/1000*1920+209*123/125
=19.2*135-14.4*19.2+209*(1-2/125)
=19.2*(135-14.4)+209-418/125
=(20-0.8)*120.6+209-418*8/1000
=2412-96.48+209-3.344
=2621-99.824
=2521.176
1/1*3+1/3*5+1/5*7+.+1/97*99
=[(1-1/3)+(1/3-1/5)+(1/5-1/7)+.+(1/97-1/99)]÷2
=(1-1/99)÷2
=49/99
1/8128+1/254+1/508+1/1016+1/2032+1/4064+1/8128
=1/8128+1/8128+1/4064+1/2032+1/1016+1/508+1/254
=1/4064+1/4064+1/2032+1/1016+1/508+1/254
=1/2032+1/2032+1/1016+1/508+1/254
=1/1016+1/1016+1/508+1/254
=1/508+1/508+1/254
=1/254+1/254
=1/127
44/45*37-8/45
=4/45*(11*37-2)
=4/45*(407-2)
=4/45*405
=36
3/4*17+0.25*29
=1/4*(3*17+29)
=1/4*(51+29)
=1/4*80
=20
12/13/(53.9*2/3)
=
2.6/[(7/12-5/16)*1.6]
=2.6/[7*1.6/12-5*1.6/16]
=2.6/[28/30-1/2]
=2.6*30/13
=6