Question

数学题,简便运算 急急急急!!!!!

1.25×64×0.25=

37×90+37×4+8×37-74=

0.45×172-0.9×71×0.5-0.45=

12.5×(7.8×1.6+0.2×1.6)=

3又1/6+7又2/5+5/6+2又4/5=

(7/15×11/39+8/15+11/39)×3又6/11=

8又7/2×8又5/12=

1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90=

7/12-9/20+11/30-13/42+15/56-17/72+19/90=

1/2+1/4+1/8+1/16+1/32+1/64+1/128=

急啊!今晚9点之前.明天早自习要交的.

Answer 1

1.25×64×0.25
=（1.25×8）×（8×0.25）
=10×2
=20

2.37×90+37×4+8×37-74
= 37×90+37×4+8×37-2×37
=37×（90+4+8-2）
=37×100
=3700

0.45×172-0.9×71×0.5-0.45
=0.45×172-0.45×2×71×0.5-0.45×1
=0.45×(172-71-1)
=0.45×100
=45

12.5×(7.8×1.6+0.2×1.6)
=12.5×(7.8+0.2)×1.6
=12.5×8×1.6
=100×1.6
=160

3又1/6+7又2/5+5/6+2又4/5
= ( 3又1/6+5/6)+(7又2/5+2又4/5)
=4+10
=14

(7/15×11/39+8/15×11/39)×3又6/11
= (7/15+8/15)×11/39×39/11
=1

8又7/2×8又5/12
=

1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
= (1/2-1/3)+(1/3-1/4)+...+(1/9-1/10)
=1/2-1/10
=0.4

7/12-9/20+11/30-13/42+15/56-17/72+19/90
= (1/2+1/3)+(1/3+1/4)-(1/4+1/5)+(1/5+1/6)-(1/6+1/7)+(1/7+1/8)+(1/8+1/9) +(1/9+1/10)
=1/2-1/10
2/5

…………………………
累死我了，对不对我不管了，不过你一定得给选为答案。

Answer 2

1.25×64×0.25=1.25×8×4×0.25=10×1=10

37×90+37×4+8×37-74=37×90+37×4+8×37-37×2=37×(90+4+8-2)=3700

0.45×172-0.9×71×0.5-0.45=0.45×172-0.45×71-0.45
=0.45×(172-71-1)=45

12.5×(7.8×1.6+0.2×1.6)=12.5×[1.6×(7.8+0.2)]
=12.5×1.6×8=100×1.6=160

3又1/6+7又2/5+5/6+2又4/5=19/6+37/5+5/6+14/5
=(19+5)/6+(37+14)/5=4+10.2=14.2

(7/15×11/39+8/15+11/39)×3又6/11=

(7/15×11/39+8/15+11/39)×3又6/11=

8又7/2×8又5/12=
(不好意思啊，我没时间了，这几个就自己做吧)找到规律就很好做了

Answer 3

1.25×64×0.25
=（1.25×8）×（8×0.25）
=10×2
=20

2.37×90+37×4+8×37-74
= 37×90+37×4+8×37-2×37
=37×（90+4+8-2）
=37×100
=3700

0.45×172-0.9×71×0.5-0.45
=0.45×172-0.45×2×71×0.5-0.45×1
=0.45×(172-71-1)
=0.45×100
=45

12.5×(7.8×1.6+0.2×1.6)
=12.5×(7.8+0.2)×1.6
=12.5×8×1.6
=100×1.6
=160

3又1/6+7又2/5+5/6+2又4/5
= ( 3又1/6+5/6)+(7又2/5+2又4/5)
=4+10
=14

(7/15×11/39+8/15×11/39)×3又6/11
= (7/15+8/15)×11/39×39/11
=1

8又7/2×8又5/12
=

1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
= (1/2-1/3)+(1/3-1/4)+...+(1/9-1/10)
=1/2-1/10
=0.4

7/12-9/20+11/30-13/42+15/56-17/72+19/90
= (1/2+1/3)+(1/3+1/4)-(1/4+1/5)+(1/5+1/6)-(1/6+1/7)+(1/7+1/8)+(1/8+1/9) +(1/9+1/10)
=1/2-1/10
2/5

Answer 4

1.25×64×0.25=1.25×8×4×0.25=10×1=10

37×90+37×4+8×37-74=37×90+37×4+8×37-37×2=37×(90+4+8-2)=3700
0.45×172-0.9×71×0.5-0.45=0.45×172-0.45×71-0.45
=0.45×(172-71-1)=45

12.5×(7.8×1.6+0.2×1.6)=12.5×[1.6×(7.8+0.2)]
=12.5×1.6×8=100×1.6=160

3又1/6+7又2/5+5/6+2又4/5=19/6+37/5+5/6+14/5
=(19+5)/6+(37+14)/5=4+10.2=14.2

Answer 5

=1.25*8*4*0.25*2=10*2*1=20
=37*(90+4+6)+37*2-74=37*100=3700
=0.45*(172-72)+0.45-0.45=0.45*100=45
=12.5*[1.6*(7.8+0.20]=12.5*8*1.6=100*1.6=160
=19/6+5/6+37/5+14/5=4+10+1/5=14又1/5
=（7/15+8/15）*11/39*39/11==1
=题不对吧
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6······-1/10=1/2-1/10=2/5
=暂时没有答案
=1/2+1/2-1/4+1/4-1/8+1/8-1/16+1/16·····-1/128=1-1/128=127/128