98x199用简便方法怎么计算,
问题描述:
98x199用简便方法怎么计算,
答
98x199
=(100-2)x199
=100x199-2x199
=19900-198
=19502
98x199
=98x(200-1)
=98x200-98x1
=19600-98
=19502