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脱式计算①9028-(4028+523)-477  ②878-[8-(2.125-0.125

2022-08-14 02:43:15 问答库 阅读 200 次

问题详情

脱式计算
①9028-(4028+523)-477  
②87

8

-[8-(2.125-0.125÷1

8

)]
③31

8

÷[(45

12

-313

24

)×4

7

+(31

18

-27

12

)×110

17

]
④(1-1

2×2

)(1-1

3×3

)(1-1

4×4

)…(1-1

2001×2001

)

参考答案

(1)9028-(4028+523)-477
=(9028-4028)-(523+477),
=5000-1000,
=4000;

(2)878-[8-(2.125-0.125÷18)]
=878-[8-(218-18÷18)],
=878-[8-(218-1)],
=878-[8-118],
=878+118-8,
=10-8
=2;

(3)318÷[(4512-31324)×47+(3118-2712)×11017]
=258÷[(5312-8524)×47+(5518-3112)×2717],
=258÷[2124×47+1736×2717],
=258÷[12+34],
=258×45,
=52;

(4)(1-12×2)(1-13×3)(1-14×4)…(1-12001×2001)
=1×32×2×2×43×3×3×54×4×…×1999×20012000×2000×2000×20022001×2001,
=12×20022001,
=10012001.

考点: