| 选择适合你的方法计算,并写出过程. (1)723-(223+311)-89 (2)(75+25×4)÷25 (3)602×110-110-110 (4)32×32+32×69-32 (5)[1178-12×(84+5)]÷5 (6)2920÷[160÷(21+19)] (7)125×(25×48) (8)3×999+3+99×5+5+7+7×9. |
| (1)723-(223+311)-89, =(723-223)-(311+89), =500-400, =100; (2)(75+25×4)÷25, =(75+100)÷25, =175÷25, =7; (3)602×110-110-110, =110×(602-1-1), =110×600, =66000; (4)32×32+32×69-32, =32×(32+69-1), =32×100, =3200; (5)[1178-12×(84+5)]÷5, =[1178-12×89]÷5, =[1178-1068]÷5, =110÷5, =22; (6)2920÷[160÷(21+19)], =2920÷[160÷40], =2920÷4, =730; (7)125×(25×48), =125×25×(8×6), =(125×8)×(25×6), =1000×150, =150000; (8)3×999+3+99×5+5+7+7×9, =3×(999+1)+5×(99+1)+7×(1+9), =3×1000+5×100+7×10, =3000+500+70, =3570. |
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