679X670X671减678X670X672等于多少的计算方法
问题描述:
679X670X671减678X670X672等于多少的计算方法
答
679X670X671减678X670X672
=670x(679x671-678x672)
=670x([(678+1)x671-678x672]
=670x(671-678)
=670x(-7)
=-4690