Question

65乘13.5的简便计算

Answer 1

65*13.5=6.5*10*(13+0.5)

=6.5*(6.5*2+0.5)*10

=(6.5*6.5*2+6.5*0.5)*10

=(42.25*2+3.25)*10.(6.5*6.5=6*7+0.25)

=(84.5+3.25)*10

=87.75*10

=877.5