7/8-1/6+1/4 1-【3/4-2/9] 1/4+3/7+1/2 用简便方法脱式计算
7/8-1/6+1/4 1-【3/4-2/9] 1/4+3/7+1/2 用简便方法脱式计算
7/8-1/6+1/4=7/8+2/8-1/6=9/8-1/6=27/24-4/24=23/24
1-【3/4-2/9]=1-3/4+2/9=1/4+2/9=9/36+8/36=17/36
1/4+3/7+1/2 =1/4+2/4+3/7=3/4+3/7=21/28+12/28=33/28=1又5/28
1/2-5/6×1/2 3/4×8/9-1/3 7/9+7/9×8 亲～～～要用简便方法计算
1/2-5/6x1/2=1x1/2-5/6x1/2=(1-5/6)x1/2=1/6x1/2=1/12
3/4x8/9-1/3=3/4x8/3x1/3-1/3=2x1/3-1/3=(2-1)x1/3=1/3
7/9+7/9x8=7/9x(1+8)=7/9x9=7
7/10+（4/7+1/2）x7/25。[1-（1/4+3/8）】x1/4能简便的简便
=7/10+4/7*7/25+1/2*7/25
=7/10+4/25+7/50
=1
=【1-5/8】*1/4
=3/8*1/4
=3/32
1/1*2*3+1/2*3*4+1/3*4*5+1/4*5*6+1/5*6*7+1/6*7*8+1/7*8*9+1/8*9*10+1/9*10*11计算方法
1/1*2*3+1/2*3*4+1/3*4*5+1/4*5*6+1/5*6*7+1/6*7*8+1/7*8*9+1/8*9*10+1/9*10*11
=(1/2)[(1/1*2)-(1/2*3)]+(1/2)[(1/2*3)-(1/3*4)]+(1/2)[(1/3*4)-(1/4*5)]+...+(1/2)[(1/9*10)-(1/10*11)]
=(1/2)[(1/1*2)-(1/2*3)+(1/2*3)-(1/3*4)+(1/3*4)-(1/4*5)+...+(1/9*10)-(1/10*11)]
=(1/2)[(1/1*2)-(1/10*11)]
=(1/2)(1-1/2-1/10+1/11)
=(1/2)(2/5+1/11)
=(1/2)(27/55)
=27/110.
1/2*4+1/3*5+1/4*6+1/5*7+...+1/8*10+1/9*11(用简便方法计算)
1/2*4+1/3*5+1/4*6+1/5*7+...+1/8*10+1/9*11
=(1/2-1/4+1/3-1/5+1/4-1/6+1/5-1/7+……+1/8-1/10+1/9-1/11）÷2
=（1/2+1/3-1/10-1/11）÷2
=106/165÷2
=53/165
能简便的要简便：（1-3/4×2/3）÷2 [7/4-（1/3+3/4)]÷2/3 [1-（1/4+3/8）]÷9/16
（1-3/4×2/3）÷2
=(1-1/2)÷2
=1/2÷2
=1/4
[7/4-（1/3+3/4)]÷2/3
=[7/4-3/4-1/3]×3/2
=2/3×3/2
=1
[1-（1/4+3/8）]÷9/16
=[1-5/8]×16/9
=3/8×16/9
=2/3
6/5×5/9+4/5×5/9+5/9=? 7/8-7/8×1/9+7/8×8/9=? 1又1/2×3/4+1/2×3/4+3/4=?要简便运算
6/5×5/9+4/5×5/9+5/9
=6/9+4/9+5/9
=6/9+(4/9+5/9)
=2/3+1
=5/3
7/8-7/8×1/9+7/8×8/9
=7/8x(1-1/9+8/9)
=7/8x16/9
=14/9
1又1/2×3/4+1/2×3/4+3/4
=3/4x(3/2+1/2+1)
=3/4x3
=9/4
1/(1×2×3×4)+1/(2×3×4×5)+1/(3×4×5×6).....+1/(7×8×9×10)用简便方法计算
解：
1/(1×2×3×4)=[1/(1×2×3)-1/(2×3×4)]/3
1/(2×3×4×5)=[1/(2×3×4)-1/(3×4×5)]/3
1/(3×4×5×6)=[1/(3×4×5)-1/(4×5×6)]/3
…………
1/(7×8×9×10)=[1/(7×8×9)-1/(8×9×10)]/3
上面几式相加得：
1/(1×2×3×4)+1/(2×3×4×5)+1/(3×4×5×6).....+1/(7×8×9×10)
=[1/(1×2×3)-1/(2×3×4)+1/(2×3×4)-1/(3×4×5)+1/(3×4×5)-1/(4×5×6)+…+1/(7×8×9)-1(8×9×10)]/3
=[1/(1×2×3)-1/(8×9×10)]/3
=(1/6-1/720)/3
=119/2160
简便计算： (1/3-1/6+1/4)*12......3/3/7-3/7/3
(1/3-1/6+1/4)*12
=1/3x12-1/6x12+1/4x12
=4-2+3
=5
1*1/2+1/2*3/1+1/3*1/4+1/4*1/5+1/5*1/6+1/6*1/7如何用简便方法计算
1*1/2+1/2*1/3+1/3*1/4+1/4*1/5+1/5*1/6+1/6*1/7
=1-1/2+1/2-1/3+1/3....+1/6-1/7
=1-1/7
=6/7
希望能帮你忙，不懂请追问，懂了请采纳，谢谢
