等于多少用简便运算,如
(1/8+1/9+1/10+1/11)×(1/9+1/10+1/11+1/12)-(1/8+1/9+1/10+1/11+1/12)×(1/9+1/10+1/11)
=(1/9+1/10+1/11)x(1/9+1/10+1/11+1/12-1/8-1/9-1/10-1/11-1/12)+1/8x(1/9+1/10+1/11+1/12)
=1/8x(1/9+1/10+1/11+1/12-1/9-1/10-1/11)
=1/8x1/12
=1/96
可以把解题的方法,思路理清楚吗
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