巧算题目在下面求~10800/45,125*640*25*7,7200/（90/27）,24000/125/16,180

10800/45=(9*1200)/(5*9)=1200/5=240
125*640*25*7=125*8*10*8*25*7=1000*20*100*7=14000000
7200/（90/27）=(80*90)/(90/27)=80/(1/27)=80*27=2160
24000/125/16=24000*16/125=24000*16*8/125*8=3072000/1000=3072
18000/72=9*2000/(9*8)=2000/8=250
2000/280*7=2000*7/280=2000/40=50
1540/91*13=1540*13/91=220*7*13/(7*13)=220
（56*57*34）/（28*19*17）=(2*28*3*19*2*17)/(28*19*17)=2*3*2=12
875/125=(1000-125)/125=8-1=7

10800/45
=1200/5
=240
125*640*25*7
=125*8*80*25*7
=1000*2000*7
=14000 000
7200/（90/27）
=80*27
=2160
24000/125/16
=2400/(125*8*2)
=2.4/2
=1.2
...