4.5×12.6-0.26×45
=4.5×12.6-2.6×4.5
=4.5×(12.6-2.6)
=4.5×10
=450.26怎么变成2.6了？0.26×45=0.26×10×4.5=2.6×4.545怎么又变成4.5了？45=10×4.5