题目内容
(2011?盐城)用递等式计算:
①0.6-0.2×1.9÷7.6;
②5÷
-
×
;
③1.02÷(5+0.4×0.25);
④
÷(
+
)×
;
⑤3÷
×(
-
).
①0.6-0.2×1.9÷7.6;
②5÷
5 |
7 |
5 |
7 |
1 |
5 |
③1.02÷(5+0.4×0.25);
④
7 |
12 |
1 |
2 |
2 |
3 |
2 |
5 |
⑤3÷
3 |
4 |
4 |
5 |
3 |
10 |
分析:这些题目按照先算乘除,再算加减,有括号的先算扩号里面的运算顺序计算.
解答:解:①0.6-0.2×1.9÷7.6,
=0.6-0.38÷7.6,
=0.6-0.05,
=0.55;
②5÷
-
×
,
=5×
-
×
;
=7-
=6
;
③1.02÷(5+0.4×0.25),
=1.02÷(5+0.1),
=1.02÷5.1,
=0.2;
④
÷(
+
)×
,
=
÷
×
,
=
×
×
,
=
×
,
=
;
⑤3÷
×(
-
),
=3÷
×
,
=3×
×
,
=4×
,
=2.
=0.6-0.38÷7.6,
=0.6-0.05,
=0.55;
②5÷
5 |
7 |
5 |
7 |
1 |
5 |
=5×
7 |
5 |
5 |
7 |
1 |
5 |
=7-
1 |
7 |
=6
6 |
7 |
③1.02÷(5+0.4×0.25),
=1.02÷(5+0.1),
=1.02÷5.1,
=0.2;
④
7 |
12 |
1 |
2 |
2 |
3 |
2 |
5 |
=
7 |
12 |
7 |
6 |
2 |
5 |
=
7 |
12 |
6 |
7 |
2 |
5 |
=
1 |
2 |
2 |
5 |
=
1 |
5 |
⑤3÷
3 |
4 |
4 |
5 |
3 |
10 |
=3÷
3 |
4 |
1 |
2 |
=3×
4 |
3 |
1 |
2 |
=4×
1 |
2 |
=2.
点评:本题考查了基本的四则混合运算,要找清楚运算顺序,按照运算法则,仔细计算.
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