口算.89×11﹣89= 12﹣5+12﹣5= 178﹣31﹣69= 13×9÷13×9= 89÷100=13×0+13= 600÷20= 405﹣60= 16×25= 8×125=
÷50=0.12=.
= :24=5:8= :40= %
3÷ ==0.75=6: = %
3÷ ==0.6=6: = %.
3:5==9: == .