题目内容
(2008?天宁区)计算下面各题,能简算的要简算.
(1.5+0.7)×(0.09÷1.8)
÷9+
×
71.2-2.3×1.6-6.32
÷[
×(
+
)].
(1.5+0.7)×(0.09÷1.8)
8 |
15 |
1 |
9 |
7 |
15 |
71.2-2.3×1.6-6.32
1 |
9 |
4 |
7 |
2 |
3 |
1 |
4 |
分析:(1)(4)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;
(2)可根据乘法分配律计算.
(3)可在算出乘法的基础上根据一个数减两个数等于减去这两个数的和的减法性质计算.
(2)可根据乘法分配律计算.
(3)可在算出乘法的基础上根据一个数减两个数等于减去这两个数的和的减法性质计算.
解答:解:(1)(1.5+0.7)×(0.09÷1.8)
=2.2×0.05,
=0.11;
(2)
÷9+
×
=
×
+
×
,
=(
+
)×
,
=1×
,
=
;
(3)71.2-2.3×1.6-6.32
=71.2-3.68-6.32,
=71.2-(3.68+6.32),
=71.2-10,
=61.2;
(4)
÷[
×(
+
)].
=
÷[
×
],
=
÷
,
=
.
=2.2×0.05,
=0.11;
(2)
8 |
15 |
1 |
9 |
7 |
15 |
=
8 |
15 |
1 |
9 |
1 |
9 |
7 |
15 |
=(
8 |
15 |
7 |
15 |
1 |
9 |
=1×
1 |
9 |
=
1 |
9 |
(3)71.2-2.3×1.6-6.32
=71.2-3.68-6.32,
=71.2-(3.68+6.32),
=71.2-10,
=61.2;
(4)
1 |
9 |
4 |
7 |
2 |
3 |
1 |
4 |
=
1 |
9 |
4 |
7 |
11 |
12 |
=
1 |
9 |
11 |
21 |
=
7 |
33 |
点评:完成本题要细心分析式中数据的特点及内在联系,然后运用合适的方法进行计算.
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