如题所述
(1)115x26+350x45=18740。竖式计算如下图:
(2)305x72=21960。竖式计算如下图:
(3)28+735+72
=100+735
=835
(4)45x42+55
=45x2x21+55
=90x21+55
=1890+55
=1945