9.45-4.33-2.67=9.45-（4.33+2.67）=9.45-7=2.45
45×9+9×450+5×9 =45×9+90×45+45×1 =45×(9+90+1) =45×100 =4500
=9.45-（4.33+2.67）=9.45-7=2.45
