3.75×1.25×8
=3.75×(1.25×8)
=3.75×10
=37.5
4.6×20.1
=(4.6×20)+(4.6×0.1)
=92+0.46
=92.46
4.19×99+4.19
=4.19×(99+1)
=4.19×100
=419
答案已核对