8题分数的计算.1.7又5/6-6又7/12+5又9/20-4又11/30+3又13/42-2又15/56+1又17/7
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/09 09:55:05
8题分数的计算.
1.7又5/6-6又7/12+5又9/20-4又11/30+3又13/42-2又15/56+1又17/72
2.1+(1/1+2)+(1/1+2+3)……+(1/1+2+……+10)
3.【(49/12-63/20+77/30-91/42+105/56)-3又1/6】除以1/24
4.(1/1*4)+(1/4*7)+(1/7*10)+(1/10*13)……+(1/97*100)
5.(1994/1994平方-1993*1995)+6
6.1999*(3.4*69+3.5)/3.5*69-3.4
7.分数线上面:1.2*3.6*10.8+2*6*18+1/13*3/13*9/3下面:1.2*2.4*4.8+2*4*8+1/13*2/13*4/13
1.7又5/6-6又7/12+5又9/20-4又11/30+3又13/42-2又15/56+1又17/72
2.1+(1/1+2)+(1/1+2+3)……+(1/1+2+……+10)
3.【(49/12-63/20+77/30-91/42+105/56)-3又1/6】除以1/24
4.(1/1*4)+(1/4*7)+(1/7*10)+(1/10*13)……+(1/97*100)
5.(1994/1994平方-1993*1995)+6
6.1999*(3.4*69+3.5)/3.5*69-3.4
7.分数线上面:1.2*3.6*10.8+2*6*18+1/13*3/13*9/3下面:1.2*2.4*4.8+2*4*8+1/13*2/13*4/13
1.7又5/6-6又7/12+5又9/20-4又11/30+3又13/42-2又15/56+1又17/72
=(7-6+5-4+3-2+1)+(5/6-7/12+.+17/72)
=4+(1/2+1/3-1/3-1/4+.+1/8+1/9)
=4+(1/2+1/9)
=4又11/18
3.原式=(3430/840-2640/840+2156/830-1820/840+1575/840-2660/840)*24
=41/840*24
=41/35
4.1/1*4+1/4*7+1/7*10+1/10*13+~+1/97*100
=(1/3)*[(1-1/4)+(1/4-1/7)+(1/7-1/10)+...+(1/97-1/100)]
=(1/3)*(1-1/100)
=(1/3)*(99/100)
=33/100
5.1994/(1994^2-1993*1995)+6
=1994/[1994^2-(1994-1)(1994+1)]+6
=1994/[1994^2-(1994^2-1)]+6
=1994/(1994^2-1994^2+1)+6
=1994+6
=2000
用公式:(a+b)*(a-b)=a^2-b^2
6.
原式=1999*(3.4*70+0.1)/(3.4*69+3.5)
=1999*(3.4*70+0.1)/(3.4*70+0.1)
=1999
7.
(1.2*3.6*10.8+2*6*8+1/13+3/13+9/13)/(1.2*2.4*4.8+2*4*8+1/13+2/13++4/13)
=(1.2*1.2*3*1.2*9+96+1)/(1.2*1.2*2*1.2*4+64+7/13)
=(46.656+96+1)/(13.824+64+7/13)
=75
再问: 继续
再答: 2. 1+(1/1+2)+(1/1+2+3)……+(1/1+2+……+10) 1+2+3+……+n=n(n+1)/2 1/(1+2+3+……+n)=2/[n(n+1)]=2[1/n-1/(n+1)] 1+(1/1+2)+(1/1+2+3)……+(1/1+2+…+10) =1+2(1-1/2)+2(1/2-1/3)+……+2(1/10-1/11) =1+2(1-1/2+1/2-1/3+……+1/10-1/11] =1+2[1-1/11] =3-2/11 =31/11 All done!
=(7-6+5-4+3-2+1)+(5/6-7/12+.+17/72)
=4+(1/2+1/3-1/3-1/4+.+1/8+1/9)
=4+(1/2+1/9)
=4又11/18
3.原式=(3430/840-2640/840+2156/830-1820/840+1575/840-2660/840)*24
=41/840*24
=41/35
4.1/1*4+1/4*7+1/7*10+1/10*13+~+1/97*100
=(1/3)*[(1-1/4)+(1/4-1/7)+(1/7-1/10)+...+(1/97-1/100)]
=(1/3)*(1-1/100)
=(1/3)*(99/100)
=33/100
5.1994/(1994^2-1993*1995)+6
=1994/[1994^2-(1994-1)(1994+1)]+6
=1994/[1994^2-(1994^2-1)]+6
=1994/(1994^2-1994^2+1)+6
=1994+6
=2000
用公式:(a+b)*(a-b)=a^2-b^2
6.
原式=1999*(3.4*70+0.1)/(3.4*69+3.5)
=1999*(3.4*70+0.1)/(3.4*70+0.1)
=1999
7.
(1.2*3.6*10.8+2*6*8+1/13+3/13+9/13)/(1.2*2.4*4.8+2*4*8+1/13+2/13++4/13)
=(1.2*1.2*3*1.2*9+96+1)/(1.2*1.2*2*1.2*4+64+7/13)
=(46.656+96+1)/(13.824+64+7/13)
=75
再问: 继续
再答: 2. 1+(1/1+2)+(1/1+2+3)……+(1/1+2+……+10) 1+2+3+……+n=n(n+1)/2 1/(1+2+3+……+n)=2/[n(n+1)]=2[1/n-1/(n+1)] 1+(1/1+2)+(1/1+2+3)……+(1/1+2+…+10) =1+2(1-1/2)+2(1/2-1/3)+……+2(1/10-1/11) =1+2(1-1/2+1/2-1/3+……+1/10-1/11] =1+2[1-1/11] =3-2/11 =31/11 All done!
8题分数的计算.1.7又5/6-6又7/12+5又9/20-4又11/30+3又13/42-2又15/56+1又17/7
计算:8又6分之5-7又12分之7+6又20分之9-5又30分之11+4又42分之13-3又56分之15+2又72分之1
10-9又5/6+8又7/12-7又9/20+6又11/30-5又13/42+4又15/56-3又17/72+2又19/
1又2\1-2又6\5+3又12\1-4又20\19+5又30\1-6又42\41+7又56\1-8又72\71+9又9
1又1/2-2又5/6+3又1/12-4又19/20+5又1/30-6又41/42+7又1/56-8又71/72+9又1
1+2又1/6+3又1/13+4又1/20+5又1/30+6又1/42+7又1/56+8又1/72+9又1/90+10又
1又1/2+2又1/6+3又1/12+4又1/20+5又1/30+6又1/42+7又1/56+8又1/72+9又1/90
7又6分之5-6又12分之7+5又20分之9-4又30分之11+3又42分之13-2又56分之15+1又72分之17
1+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42+13又1/56+15又1/72+17又1/90
1+2又1/8+3又1/12+4又1/20+5又1/30-6又1/42+7又1/56+8又1/42+9又1/42
1 又1/2-2又5/6+3又1/12-4又19/20-5又1/30+6又41/42-7又1/56+8又71/72-9
1+2又6分之1+3又12分之1+4又20分之1+5又30分之1+6又42分之1+7又56分之1+8又78分之1+9又9