1除以0.25乘(1.28除3.2)简便运算
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1/2X3X4X5+1/3X4X5X6+1/4X5X6X7.1/97X98X99X100=?=1/3[1/2*3*4-1/3*4*5]+1/3[1/3*4*5-1/4*5*6]+1/3[1/4*5*6
裂两项相消法:完全是凑出简单的几项和差的形式进行化简:步骤一:待定系数法-----设An=1/[n(n-1)(n-2)];(n>=3,n∈N*);令An=A/(n-2)+B/(n-1)+C/n;通分后
原式=(1/2)×(1-1/3)+(1/2)×(1/3-1/5)+(1/2)×(1/5-1/7)+……+(1/2)×(1/2005-1/2007)=(1/2)×(1-1/3+1/3-1/5+1/5-1
这个题目是用裂项来做的:注意到这样的一个事实:1/k*(k+1)(k+2)=1/2*[1/k*(k+1)-1/(k+1)*(k+2)]因此原式=1/(2*3)-1/(3*4)+1/(3*4)-1/(4
1除以0.25乘(1.28除以3.2)=1/0.25*(1.28/3.2)=4*1.28/3.2=1.28/0.8=(1+0.28)/0.8=1.25+0.35=1.6
3除以1乘2+3除以2乘3+3除以3乘4+3除以4乘5+···+3除以99乘100=3×(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+……+1/99-1/100)=3×(1-1/100
原式=3.5×0.25+360×0.25+0.25×36.5=0.25×(3.5+36.5+360)=0.25×400=100
1253888469(3又1/2)÷4+360×25%+0.25×36.5=3.5×0.25+360×0.25+0.25×36.5=0.25×(3.5+360+36.5)=0.25×400=(1/4)
5.125-(3又2分之1+8分之3)=5+0.125-(3+1/2+3/8)=5+1/8-3-1/2-3/8=5-3-2/4-3/8+1/8=2-2/4-1/4=2-3/4=1又1/48分之3乘5又
方程为1X2+2X3+3X4+4X5+……2010X2011=2010x1=(2-1)^2=2^2-2X1X2+1^21=(3-2)^2=3^2-2X2X3+2^21=(4-3)^2=4^2-2X3X
10除以2:10是被除数2是除数10除以2等于510除2:2是被除数10是除数10除2等于0.2
1/[n*(n+1)*(n+2)]=[1/n-1/(n+1)]/(n+2)=[1/n-1/(n+2)]/2-[1/(n+1)-1/(n+2)]=[1/n-2/(n+1)+1/(n+2)]/21/(1*
4分之3乘2.84除以3又5分之3÷(1又2分之1乘1.42)乘1又5分之4=(4分之3÷1又1/2)乘(2.84÷1.42)×(1又4/5除以3又5分之3)=0.5×2×0.5=0.5再问:用巧算再
(1/8-5/12)*24-(-3-3)^2/(-6/3)^2=1/8*24-5/12*24-(-6)^2/(-2)^2=3-10-36/4=-7-9=-16
答案是14.4,太简单了再问:我要过程再答:12除以3等于4,二分之一等于0.5,4乘以0.5等于2,24除以15等于1.6,2加上1.6等于3.6,3.6除以0.25等于14.4,希望采纳
-2.5除以5/8乘(-1/4)=-4×(-1/4)=1—27除以2又四分之一乘4/9÷(-24)=-12×4/9÷(-24)=-16/3÷(-24)=2/9(-3/5)乘(—3又二分之一)÷(-1又
1/(1*3)+1/(3*5)+.+1/(2005*2007)=1/2*(1-1/3+1/3-1/5+.+1/2005-1/2007)=1/2*(1-1/2007)=2006/4014=1003/20
1/1*3+1/2*4+1/3*5+1/4*6+……+1/9*11=(1/1*3+1/3*5+...+1/9*11)+(1/2*4+1/4*6+...+1/8*10)=(1/1-1/3+1/3-1/5
1乘以0.4除以1乘0.4得多少?1乘0.4=0.4除1=0.4乘0.4=0.1625乘4除以0.25乘4得多少?25乘以4=100除以0.25=400乘4=1600