99×98+98的简便运算99×98+98的=98*(1+99)=98*100=9800
99Ⅹ98+98 =(99-1)Ⅹ98+98 =(99+1)X98+98 =100ⅹ98+98 =9800+98 =9898
乘法分配律为:两个数的和与一个数相乘,先将它们与这个数分别相乘,再相加,积不变.即:(a+b)×c=a×c+b×c.反过来则:a×c+b×c=(a+b)×c99×98+98= 98× ( 99+1)= 98×100=9800