几道算术题(六年级)a.6/11*17-12*3/11b.(1+1/2)*(1-1/2)*(1+1/3)*(1-1/3)*...*(1+1/9)*(1-1/9)c.1/27+505/2727+131313/272727+101010/272727d.已知:1/2-1/3=1/2*3,计算:1/2*3+1/3*4+1/4*5+1/5*6+...+1/19*20注:(/)

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几道算术题(六年级)
a.6/11*17-12*3/11
b.(1+1/2)*(1-1/2)*(1+1/3)*(1-1/3)*...*(1+1/9)*(1-1/9)
c.1/27+505/2727+131313/272727+101010/272727
d.已知:1/2-1/3=1/2*3,计算:1/2*3+1/3*4+1/4*5+1/5*6+...+1/19*20
注:(/)代表分数线.如:505/2727=2727分子505,(*)代表乘法
d题1/2-1/3=1/2*3,是2分之1-3分之1=2*3分之1的意思.

a.原式=(6*17-12*3)/11=(17-2*3)*6/11=11*6/11=6
b.原式=3/2*1/2*4/3*2/3*...*10/9*8/9
=(3/2*4/3*5/4*...*10/9)*(1/2*2/3*3/4*...*8/9)
=(10/2)*(1/9)=5/9
c.原式=1/27+(101*5)/(101*27)+(10101*13)/(10101*27)
+(10101*10)/(10101*27)
=1/27+5/27+13/27+10/27=29/27
d.原式=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+...+1/18-1/19+1/19-1/20
=1/2-1/20=9/20