题目内容
计算下面各题,能简算的就简算.
1-
|
3+
|
| ||||||||||||||||||||
|
78×150%-78×
|
|
分析:第④⑤可用乘法分配律简算,其它题目按照先算乘除再算加减,有括号的先算括号里面的运算顺序计算.
解答:解:①1-
÷
-
,
=1-
-
,
=1-(
+
),
=1-1,
=0;
②3+
×
÷
,
=3+
×
,
=3+
,
=3
;
③
÷(
-
)×
=
÷
×
,
=
×
×
,
=
;
④
×
+
÷
,
=(
+
)×
,
=1×
,
=
;
⑤78×150%-78×
=78×(150%-
),
=78×1,
=78;
⑥
×[1÷(
+
)]
=
×(1×
),
=
×
,
=
.
2 |
11 |
8 |
11 |
3 |
4 |
=1-
1 |
4 |
3 |
4 |
=1-(
1 |
4 |
3 |
4 |
=1-1,
=0;
②3+
5 |
8 |
3 |
5 |
9 |
8 |
=3+
3 |
8 |
8 |
9 |
=3+
1 |
3 |
=3
1 |
3 |
③
1 |
3 |
2 |
3 |
2 |
5 |
3 |
5 |
=
1 |
3 |
4 |
15 |
3 |
5 |
=
1 |
3 |
15 |
4 |
3 |
5 |
=
3 |
4 |
④
4 |
7 |
8 |
9 |
3 |
7 |
9 |
8 |
=(
4 |
7 |
3 |
7 |
8 |
9 |
=1×
8 |
9 |
=
8 |
9 |
⑤78×150%-78×
1 |
2 |
=78×(150%-
1 |
2 |
=78×1,
=78;
⑥
3 |
4 |
5 |
6 |
3 |
4 |
=
3 |
4 |
12 |
19 |
=
3 |
4 |
12 |
19 |
=
9 |
19 |
点评:乘法分配律是常用的简算方法,记住它的形式,灵活运用.
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