2008+2007乘2009/2008×2009-1简便运算

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2008+2007乘2009/2008×2009-1简便运算2008+2007乘2009/2008×2009-1简便运算2008+2007乘2009/2008×2009-1简便运算原式=2008+(2

2008+2007乘2009/2008×2009-1简便运算
2008+2007乘2009/2008×2009-1简便运算

2008+2007乘2009/2008×2009-1简便运算
原式=2008+(2008-1)(2008+1)/2008×2009-1
=2008+2008²-1/2008×2009-1
=2008×(2008+1)-1/2008×2009-1
=2008×2009-1/2008×2009-1
=1

(2008+2007×2009)/(2008×2009-1)
=【2008+(2008-1)×2009】/(2008×2009-1)……把2007写成“2008-1”
=(2008+2008×2009-2009)/(2008×2009-1)……计算2008-2009等于“-1”
=(2008×2009-1)/(2008×2009-1)……分子和分母相同
=1