题目内容
灵活计算(能简算的用简便方法计算)
9.47-(1.47+0.76) | 23-
|
1
| ||||||||||||||
(
|
|
67.5×2.4+3.25×24. |
分析:(1)9.47-(1.47+0.76)去掉括号,变成9.47-1.47-0.76计算简便;
(2)23-
÷
×
,先算
÷
×
,再算减;
(3)1
-(
-
)去掉括号,变成1
-
+
计算简便;
(4)把除以
变成乘以
,再利用乘法的分配律计算;
(5)把
÷
变成
×
,
÷
变成
×
,再利用乘法的分配律计算;
(6)67.5×2.4+3.25×24,把67.5×2.4变成6.75×24,再利用乘法的分配律计算.
(2)23-
35 |
9 |
3 |
8 |
15 |
7 |
35 |
9 |
3 |
8 |
15 |
7 |
(3)1
13 |
29 |
13 |
29 |
4 |
5 |
13 |
29 |
13 |
29 |
4 |
5 |
(4)把除以
13 |
16 |
16 |
13 |
(5)把
23 |
9 |
7 |
25 |
23 |
9 |
25 |
7 |
40 |
9 |
7 |
25 |
40 |
9 |
25 |
7 |
(6)67.5×2.4+3.25×24,把67.5×2.4变成6.75×24,再利用乘法的分配律计算.
解答:解;(1)9.47-(1.47+0.76),
=9.47-1.47-0.76,
=8-0.76,
=7.24;
(2)23-
÷
×
,
=23-
×
×
,
=23-
,
=
;
(3)1
-(
-
),
=1
-
+
,
=1
;
(4)(
+
)÷
,
=(
+
)×
,
=
×
+
×
,
=6+1,
=7;
(5)
÷
+
÷
,
=
×
+
×
,
=(
+
)×
,
=7×
,
=25;
(6)67.5×2.4+3.25×24,
=6.75×24+3.25×24,
=(6.75+3.25)×24,
=10×24,
=240.
=9.47-1.47-0.76,
=8-0.76,
=7.24;
(2)23-
35 |
9 |
3 |
8 |
15 |
7 |
=23-
35 |
9 |
8 |
3 |
15 |
7 |
=23-
200 |
9 |
=
7 |
9 |
(3)1
13 |
29 |
13 |
29 |
4 |
5 |
=1
13 |
29 |
13 |
29 |
4 |
5 |
=1
4 |
5 |
(4)(
39 |
8 |
13 |
16 |
13 |
16 |
=(
39 |
8 |
13 |
16 |
16 |
13 |
=
39 |
8 |
16 |
13 |
13 |
16 |
16 |
13 |
=6+1,
=7;
(5)
23 |
9 |
7 |
25 |
40 |
9 |
7 |
25 |
=
23 |
9 |
25 |
7 |
40 |
9 |
25 |
7 |
=(
23 |
9 |
40 |
9 |
25 |
7 |
=7×
25 |
7 |
=25;
(6)67.5×2.4+3.25×24,
=6.75×24+3.25×24,
=(6.75+3.25)×24,
=10×24,
=240.
点评:考查了运算定律与简便运算,四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算律简便计算.
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灵活计算(能简算的用简便方法计算)
9.47-(1.47+0.76) | 23-÷× | 1-(-) |
(+)÷ | ÷+÷ | 67.5×2.4+3.25×24. |