5.7×9.9+0.57=5.7×9.9+5.7×0.1=5.7×(9.9+0.1)=5.7×10=57
5.7X9.9+0.57=0.57X(99+1)=0.57X100=57
5.7*9.9+0.57=5.7*9.9+5.7*0.1=5.7*(9.9+0.1)=5.7*10=57
5.7x9.9+0.57 =5.7x9.9+5.7x0.1=5.7x(9.9+0.1)=5.7x10=57