解出下面四个简便计算题.

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解出下面四个简便计算题.解出下面四个简便计算题.解出下面四个简便计算题.=(1+1/4+1/5+1/6+1/7)x(1/4+1/5+1/6)-(1/4+1/5+1/6+1/7)x[1+(1/4+1/5

解出下面四个简便计算题.
解出下面四个简便计算题.

解出下面四个简便计算题.

=(1+1/4+1/5+1/6+1/7)x(1/4+1/5+1/6)-(1/4+1/5+1/6+1/7)x[1+(1/4+1/5+1/6)]

=(1/4+1/5+1/6)+(1/4+1/5+1/6+1/7)x(1/4+1/5+1/6)-(1/4+1/5+1/6+1/7)-

                                                                                                      (1/4+1/5+1/6+1/7)x(1/4+1/5+1/6)

=(1/4+1/5+1/6)-(1/4+1/5+1/6+1/7)

=37/60-[37/60+1/7]

=-1/7

 

2012÷2012又2012/2013

=2012÷[(2012x2013+2012)/2013]

=2012÷[(2012x2014)/2013]

=2012x[2013/(2012x2014)]

=2013/2014

2012÷2012又2012/2013

=1/[(2012又2012/2013)/2012]

=1/[(2012+2012/2013)/2012]

=1/(1+1/2013)

=1/(2014/2013)

=2013/2014

 

(4/9)x[3/4-(7/16-1/4)]

=(4/9)x[3/4-7/16+1/4]

=(4/9)x[1-7/16]

=(4/9)x[9/16]

=1/4

 

[14.8+(6又2/7-4.5)x1又3/25]+2又2/3

=[14.8+(6又2/7-4.5)x1又3/25]+2又2/3

=[74/5+(44/7-9/2)x28/25]+8/3

=[74/5+(44/7)x(28/25)-(9/2)x(28/25)]+8/3

=[74/5+(44)x(4/25)-(9)x(14/25)]+8/3

=[74/5+(176/25)-(126/25)]+8/3

=[74/5+2]+8/3

=[84/5]+8/3

=(252+40)/15

=292/15

=19又7/15

 

[14.8+(6又2/7-4.5)x1又3/25]+2又2/3

=[14.8+(6又2/7-4.5)x1又3/25]+2又2/3

=[14.8+(44/7-9/2)x28/25]+2又2/3

=[14.8+(44/7)x(28/25)-(9/2)x(28/25)]+2又2/3

=[14.8+(44)x(4/25)-(9)x(14/25)]+2又2/3

=[14.8+(176/25)-(126/25)]+2又2/3

=[14.8+2]+2又2/3

=[16.8]+2又2/3

=(16+2)+(4/5+2/3)

=18+(12+10)/15

=18+22/15

=18+1+7/15

=19又7/15

第二题=2013/2014
第三题=4/9-7/36=1/4