计算下面各题,能简算的要用简便方法计算.
1个回答

①250×8-245,

=2000-245,

=1755;

②10.15-6.25-3.75+7.85,

=10.15+7.85-(6.25+3.75),

=18-10,

=8;

7

8 ×

5

9 +

5

9 ÷8,

=

7

8 ×

5

9 +

5

9 ×

1

8 ,

=(

1

8 +

7

8 )×

5

9 ,

=1×

5

9 ,

=

5

9 ;

④24+5÷(3-2.5),

=24+5÷0.5,

=24+10,

=34;

10

13 ×(

3

4 +1÷

5

6 ),

=

10

13 ×(

3

4 +

6

5 ),

=

10

13 ×(

15

20 +

24

20 ),

=

10

13 ×

39

20 ,

=

3

2 ;

⑥2÷[4×(

1

2 -

1

3 )]

=2÷[4×(

3

6 -

2

6 )],

=2÷[4×

1

6 ],

=2÷

2

3 ,

=3.