脫式計算.你是最棒的!
6.5×8+3.5×8-44    
8.5+(5.6-4.8)×13      1.9-1.9×(1.9-1.9)
7
8
×29+
1
8
×29+29        
1
100
÷
1
2000
×
1
10
7
25
×101-
7
25
49.5×10
3
5
-(50-
1
2
)×0.6     
7
11
×4
14
19
+5
5
19
÷1
4
7
+
7
11
      
6
13
÷[
7
11
×(1-
3
7
)]
897×
3
8
-37.5%+104×0.375
[
1
3
+
8
33
×(
5
6
-0.375)]÷
2
3
4
5
+9
4
5
+99
4
5
+999
4
5
+9999
4
5
               
4
4
5
-(2
4
5
+
5
12
分析:
 (1)先根據(jù)四則混合運算的順序確定應(yīng)該先算什么后算什么:只有一級運算時,從左到右計算;有兩級運算時,先算乘除,后算加減.有一層括號時,先算括號里的;有多層括號時,先算小括號里的. 
(2)能夠運用簡便算法的題目,根據(jù)所學(xué)定律選擇適合的簡便方法.
解答:解:
(1)6.5×8+3.5×8-44,
=(6.5+3.5)×8-44,
=10×8-44,
=80-44,
=36; 

(2)8.5+(5.6-4.8)×13,
=8.5+0.8×13,
=8.5+10.4,
=18.9;


(3)1.9-1.9×(1.9-1.9),
=1.9-1.9×0,
=1.9-0,
=1.9;

(4)
7
8
×29+
1
8
×29+29
=(
7
8
+
1
8
+1)×29,
=2×29,
=58;

(5)1×
1
100
÷
1
2000
×
1
10

=
1
100
×2000×
1
10
,
=20×
1
10

=2;

(6)
7
25
×101-
7
25
,
=(101-1)×
7
25

=100×
7
25
,
=28;

(7)49.5×10
3
5
-(50-
1
2
)×0.6,
=49.5×10.6-49.5×0.6,
=49.5×(10.6-0.6),
=49.5×10,
=495;

(8)
7
11
×4
14
19
+5
5
19
÷1
4
7
+
7
11
,
=
7
11
×4
14
19
+5
5
19
×
7
11
+
7
11
,
=(4
14
19
+5
5
19
+1)×
7
11
,
=11×
7
11
,
=7;

(9)
6
13
÷[
7
11
×(1-
3
7
)],
=
6
13
÷[
7
11
×
4
7
],
=
6
13
÷
4
11

=
6
13
×
11
4
,
=
33
26
;

(10)897×
3
8
-37.5%+104×0.375,
=897×0.375-0.375+104×0.375,
=(897-1+104)×0.375,
=1000×0.375,
=375;

(11)[
1
3
+
8
33
×(
5
6
-0.375)]÷
2
3
,
=[
1
3
+
8
33
×(
5
6
-
3
8
)]÷
2
3
,
=[
1
3
+
8
33
×
11
24
2
3

=[
1
3
+
1
9
2
3
,
=
4
9
×
3
2
,
=
2
3
;

(12)
4
5
+9
4
5
+99
4
5
+999
4
5
+9999
4
5
,
=(9+99+999+9999)+
4
5
×5,
=9+99+999+9999+4,
=(9+1)+(99+1)+(999+1)+(9999+1),
=10+100+1000+10000,
=11110;

(13)4
4
5
-(2
4
5
+
5
12
),
=4
4
5
-2
4
5
-
5
12
,
=2-
5
12

=
19
12
點評:此題主要考察四則混合運算的順序和簡便算法的靈活運用,要根據(jù)每一題的特點選擇適合的方法.
練習(xí)冊系列答案
相關(guān)習(xí)題

科目:小學(xué)數(shù)學(xué) 來源: 題型:

脫式計算.你是最棒的!
1-
1
2
×{1-
1
3
×[1-
1
4
×(1-
1
5
)]} 
55
1
17
×
17
18
+145
1
11
×
11
12
9999×9999+19999
77×13+255×999-510
1
2
x-3+(2x-5)=17
55%x-(0.25x+0.6)=0.6.

查看答案和解析>>

科目:小學(xué)數(shù)學(xué) 來源: 題型:解答題

脫式計算.你是最棒的!
1-數(shù)學(xué)公式×{1-數(shù)學(xué)公式×[1-數(shù)學(xué)公式×(1-數(shù)學(xué)公式)]}
55數(shù)學(xué)公式×數(shù)學(xué)公式+145數(shù)學(xué)公式×數(shù)學(xué)公式9999×9999+19999
77×13+255×999-510數(shù)學(xué)公式x-3+(2x-5)=1755%x-(0.25x+0.6)=0.6.

查看答案和解析>>

同步練習(xí)冊答案