下面各题能简便计算的要简便计算. 7 25 ÷[( 3 4 - 2 5 )× 2 5 ] 0.25×3.2×12.5 2

1个回答

  • (1)

    7

    25 ÷[(

    3

    4 -

    2

    5 )×

    2

    5 ],

    =

    7

    25 ÷[

    7

    20 ×

    2

    5 ],

    =

    7

    25 ÷

    7

    50 ,

    =2;

    2)0.25×3.2×12.5,

    =0.25×(4×0.8)×12.5,

    =(0.25×4)×(0.8×12.5),

    =1×1,

    =1;

    (3)22×(

    2

    11 +

    3

    16 )×8,

    =22×

    2

    11 ×8+22×

    3

    16 ×8,

    =32+33,

    =65;

    (4)

    9

    35 ×

    8

    11 +

    3

    35 ×

    9

    11 ,

    =

    8

    35 ×

    9

    11 +

    3

    35 ×

    9

    11 ,

    =(

    8

    35 +

    3

    35 )×

    9

    11 ,

    =

    11

    35 ×

    9

    11 ,

    =

    9

    35 ;

    (5)999

    8

    9 +99

    8

    9 +9

    8

    9 ,

    =999

    8

    9 +99

    8

    9 +9

    8

    9 +(

    1

    9 +

    1

    9 +

    1

    9 -

    1

    3 ),

    =(999

    8

    9 +

    1

    9 )+(99

    8

    9 +

    1

    9 )+(9

    8

    9 +

    1

    9 )-

    1

    3 ,

    =1000+100+10-

    1

    3 ,

    =1110-

    1

    3 ,

    =1109

    2

    3 ;

    (6)

    1

    10 +

    1

    40 +

    1

    88 +

    1

    154 ,

    =

    1

    2×5 +

    1

    5×8 +

    1

    8×11 +

    1

    11×14 ,

    =

    1

    3 ×[(

    1

    2 -

    1

    5 )+(

    1

    5 -

    1

    8 )+(

    1

    8 -

    1

    11 )+(

    1

    11 -

    1

    14 )],

    =

    1

    3 ×[

    1

    2 -

    1

    5 +

    1

    5 -

    1

    8 +

    1

    8 -

    1

    11 +

    1

    11 -

    1

    14 ],

    =

    1

    3 ×[

    1

    2 -

    1

    14 ],

    =

    1

    3 ×

    3

    7 ,

    =

    1

    7 .