简便运算：302×99+138,
问题描述：
简便运算：302×99+138,
答
302x(100-1)+138=30200-164=30036
答
302×99+138=302(100-1)+138=30200-302+138=30036
答
302×99+138
=302x(100-1)+140-2
=30200-302+140-2
=30200-300-2+140-2
=30200+140-300-4
=30040-4
=30036