Question

脫式計算下面各題
420-375÷25×8+263=
8.46+2.8×（0.9-0.35）-0.67=
5-3

1

5

×

3

4

+6

3

5

÷11=
5.67×[1÷(3

1

10

-3.09)]
[2

3

8

+(4.5-2

2

3

）÷1

3

8

]÷

1

3

=
6.5×[3

1

3

÷（4-2.5×

14

15

）]=

Answer 1

分析：根據分數(shù)、小數(shù)、整數(shù)的四則混合運算的運算順序解答即可：先算乘除后算加減，有括號的要先算括號里面的．

解答：解：420-375÷25×8+263
=420-120+263
=300+263
=563；

8.46+2.8×（0.9-0.35）-0.67
=8.46+2.8×0.55-0.67
=8.46+1.54-0.67
=10-0.67
=9.33；

5-3

1

5

×

3

4

+6

3

5

÷11
=5-

16

5

×

3

4

+

33

5

×

1

11

=5-

12

5

+

3

5

=5-（

12

5

-

3

5

）
=5-1

4

5

=3

1

5

；

5.67×[1÷(3

1

10

-3.09)]
=5.67×[1÷0.01]
=5.67×100
=567；

[2

3

8

+(4.5-2

2

3

）÷1

3

8

]÷

1

3

=[2

3

8

+

11

6

×

8

11

]÷

1

3

=

89

24

×3
=

89

8

；

6.5×[3

1

3

÷（4-2.5×

14

15

）]
=6.5×[3

1

3

÷（4-

7

3

）]
=6.5×[

10

3

×

3

5

]
=6.5×2
=13．

點評：考查了四則混合運算．注意運算順序和運算法則．