题目内容
脱式计算.(能简算的要简算.)
(1)(
|
(2)19÷(
| ||||||||||||
(3)55
|
(4)0.6×
| ||||||||||||
(5)(
|
(6)5×(
|
分析:(1)先算小括号里面的减法,再算括号外的除法,最后算括号外的加法;
(2)先算小括号里面的加法,再算括号外的除法;
(3)先把除法变成乘法,55
分解成55+
,然后运用乘法分配律简算;
(4)0.6=60%=
,所以运用乘法分配律简算;
(5)运用乘法分配律简算;
(6)先运用乘法分配律简算,再算括号外的减法.
(2)先算小括号里面的加法,再算括号外的除法;
(3)先把除法变成乘法,55
11 |
14 |
11 |
14 |
(4)0.6=60%=
3 |
5 |
(5)运用乘法分配律简算;
(6)先运用乘法分配律简算,再算括号外的减法.
解答:解:(1)(
-
)÷
+
,
=
÷
+
,
=
+
,
=
;
(2)19÷(
+
),
=19÷
,
=12;
(3)55
÷11,
=(55+
)×
,
=55×
+
×
,
=5+
,
=5
;
(4)0.6×
+60%×
+
×
,
=0.6×(
+
+
),
=0.6×1,
=0.6;
(5)(
+
-
)×24,
=
×24+
×24-
×24,
=8+3-4,
=11-4,
=7;
(6)5×(
+
)-
,
=5×
+5×
-
,
=
+
-
,
=
-
,
=
.
1 |
2 |
1 |
3 |
1 |
3 |
1 |
6 |
=
1 |
6 |
1 |
3 |
1 |
6 |
=
3 |
6 |
1 |
6 |
=
2 |
3 |
(2)19÷(
3 |
4 |
5 |
6 |
=19÷
19 |
12 |
=12;
(3)55
11 |
14 |
=(55+
11 |
14 |
1 |
11 |
=55×
1 |
11 |
11 |
14 |
1 |
11 |
=5+
1 |
14 |
=5
1 |
14 |
(4)0.6×
18 |
25 |
6 |
25 |
3 |
5 |
1 |
25 |
=0.6×(
18 |
25 |
6 |
25 |
1 |
25 |
=0.6×1,
=0.6;
(5)(
1 |
3 |
1 |
8 |
1 |
6 |
=
1 |
3 |
1 |
8 |
1 |
6 |
=8+3-4,
=11-4,
=7;
(6)5×(
2 |
15 |
1 |
20 |
5 |
12 |
=5×
2 |
15 |
1 |
20 |
5 |
12 |
=
2 |
3 |
1 |
4 |
5 |
12 |
=
11 |
12 |
5 |
12 |
=
1 |
2 |
点评:乘法分配律是常用的简便运算的方法,要熟练掌握,灵活运用.
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