7.28+1.39-4.28 9.06-5.09+0.94-4.91 67×135-57×135
560×72+29×560-560 25×64×125 3333×3333+9999×8889
①(227+49)÷12 ②864÷[(32-28)×12]
③88×125 ④24×97+24×3