狮牌雪茄还有卖么:数学简便算

1、9.75+99.75+999.75+9999.75
=(10-0.25)+(100-0.25)+(1000-0.25)+(10000-0.25)
=10+100+1000+10000-0.25*4
=11110-1
=11109
2、1989*1999-1988*2000
=1989*(2000-1)-1988*2000
=(1989-1988)*2000-1989
=2000-1989
=11
3、51/697*23*451/115
=[(3*17)/(17*41)]*23*[(11*41)/23*5]
=33/5
4、125*25*3232*69
=125*25*(8*4*101)*69
=(125*8)*(25*4)*101*69
=1000*100*(100+1)*69
=690000000+6900000
=696900000

9.75+99.75+999.75+9999.75
=9.75+0.25+99.75+0.25+999.75+0.25+9999.75+0.25-1
=11110-1=11109
1989*1999-1988*2000
=(1989*2000-1989)-(1989*2000-2000)
=2000-1989=11
51/697*23*451/115
=17*3/(17*41)*23*41*11/(23*5)
=33/5
125*25*3232*69
=125*25*8*4*101*69
=1000*100*6969
=696900000

9.75+99.75+999.75+9999.75
=10-0.25+100-0.25+1000-0.25+10000-0.25
=11110-0.25*4
=11110-1
=11109

1989*1999-1988*2000
=(1988+1)*1999-1988*(1999+1)
=1988*1999+1999-1988*1999-1988
=1999-1998
=11

51/697*23*451/115
=3/41*23*451/115
=3*23*11/115
=3*11/5
=33/5

125*25*3232*69
=125*25*(8*4*101)*69
=125*8*25*4*101*69
=1000*100*6969
=696900000

1
10-0.25+100-0.25+1000-0.25+10000-0.25
=11110-1
=11109

2
1989*1999-1988*2000
=1989*(2000-1)-1988*2000
=1989*2000-1988*2000-1989
=2000-1989
=11

3
51*23*451/(697*115)
=3*17*23*11*41/(41*17*23*5)
=33/5
=6.6

4
125*25*4*8*101*69
=1000*100*101*69
=696900000

9.75+99.75+999.75+9999.75 =10+100+1000+10000-4*0.25=11110-1=11109
1989*1999-1988*2000
=1989*(2000-1)-1988*2000
=1989*2000-1988*2000-1989*1
=(1989-1988)*2000-1989
=2000-1989
=11
51/697*23*451/115
=51/697*451/5 23/115=1/5
=(51*451)/(697*5)
=(3*17*11*41)/(17*41*5) 697=17*41
=(3*11)/5
=33/5
125*25*3232*69
=25*5*25*101*4*4*2*69
=25*4*25*4*101*10*69
=100000*101*69
=100000*6969
=696900000

(1)=10+100+1000+10000-0.25-0.25-0.25-0.25=11110-1=11109
(2)=1989*(2000-1)-1988*2000=(1989-1988)*2000-1989=11
(3)=3*17*23*41*11/(697*115)=3*17*23*41*11/(41*17*23*5)=11*3/5=6.6
(4)=125*25*32*101*69=125*8*25*4*101*69=1000*100*6969=696900000