题目内容
| 计算下面各题.(能简算的要简算) 3.68×〔1÷(
|
|
(
| ||||||||||||||||||
(4-3.5×
|
2-(11.9-8.4×
|
4.97×
|
分析:算式(1)(3)(4)(5)根据四则混合运算的运算顺序计算即可:先算乘除,再算加减,有括号的要先算括号里面的;
算式(2)(6)可根据乘法分配律进行计算.
算式(2)(6)可根据乘法分配律进行计算.
解答:解:(1)3.68×[1÷(
-2.09)]
=3.68×[1÷(2.1-2.09)],
=3.68×[1÷0.01],
=3.68×100,
=368;
(2)
×(
+
)+
=
×
+
×
+
,
=2+3+
,
=5
;
(3)(
+
)×(
-
)
=
×
,
=
;
(4)(4-3.5×
)÷
=(4-
)×
,
=
×
,
=
;
(5)2-(11.9-8.4×
)
=2-(11.9-11.2),
=2-0.7,
=1.3;
(6)4.97×
+4.97×
=4.97×(
+
),
=4.97×1,
=4.97.
| 21 |
| 10 |
=3.68×[1÷(2.1-2.09)],
=3.68×[1÷0.01],
=3.68×100,
=368;
(2)
| 12 |
| 5 |
| 5 |
| 6 |
| 5 |
| 4 |
| 7 |
| 8 |
=
| 12 |
| 5 |
| 5 |
| 6 |
| 12 |
| 5 |
| 5 |
| 4 |
| 7 |
| 8 |
=2+3+
| 7 |
| 8 |
=5
| 7 |
| 8 |
(3)(
| 7 |
| 9 |
| 2 |
| 3 |
| 6 |
| 7 |
| 3 |
| 14 |
=
| 13 |
| 9 |
| 9 |
| 14 |
=
| 13 |
| 14 |
(4)(4-3.5×
| 2 |
| 3 |
| 10 |
| 9 |
=(4-
| 7 |
| 3 |
| 9 |
| 10 |
=
| 5 |
| 3 |
| 9 |
| 10 |
=
| 3 |
| 2 |
(5)2-(11.9-8.4×
| 4 |
| 3 |
=2-(11.9-11.2),
=2-0.7,
=1.3;
(6)4.97×
| 1 |
| 9 |
| 8 |
| 9 |
=4.97×(
| 1 |
| 9 |
| 8 |
| 9 |
=4.97×1,
=4.97.
点评:完成本题要细心,注意通分约分及小数、分数之间的互化.
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