(7.5-2.3x0.4)÷0.02=(7.5-0.92)÷0.02=6.58÷0.02=329(7.5-2.3x0.4)x0.02=(7.5-0.92)x0.02=6.58x0.02=0.1316谢谢，请采纳
(7.5-2.3X0.4)0.02(7.5-2.3X0.4)÷0.02=（7.5-1.12）÷0.02=6.38÷0.02=319
