脱式计算(③④⑤小题用简便方法).

1个回答

  • ①635+9030÷86×13,

    =635+105×13,

    =635+1365,

    =2000;

    ②4.1-2.56÷(0.18+0.62),

    =4.1-2.56÷0.8,

    =4.1-3.2,

    =0.9;

    ③45×101,

    =45×(100+1),

    =4500+45,

    =4545;

    ④5.7-(1.9-1.3),

    =5.7-1.9+1.3,

    =5.7+1.3-1.9,

    =7-1.9,

    =5.1;

    98

    99 +

    98

    99 ×98,

    =

    98

    99 ×(1+98),

    =

    98

    99 ×99,

    =98;

    4

    5 ÷〔

    5

    8 ×(

    1

    6 +

    1

    3 )〕,

    =

    4

    5 ÷[

    5

    8 ×(

    1

    6 +

    2

    6 )],

    =

    4

    5 ÷[

    5

    8 ×

    1

    2 ],

    =

    4

    5 ÷

    5

    16 ,

    =

    4

    5 ×

    16

    5 ,

    =

    64

    25 ,

    =2

    14

    25 .