作业帮解出下面四个简便计算题.
来源：学生作业帮 编辑：作业帮 分类：数学作业 时间：2024/05/26 13:26:26
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)]=2013/20142012÷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