题目内容
脱式计算:
0.75÷0.25+
×
(8.6×0.5-
)÷12
÷[
-(
+
)]
[800×(1+25%)-360×1.5]÷25%
15-[
+(2.5-
)]÷0.125.
0.75÷0.25+
3 |
4 |
2 |
3 |
(8.6×0.5-
31 |
10 |
39 |
10 |
15 |
4 |
4 |
3 |
1 |
6 |
[800×(1+25%)-360×1.5]÷25%
15-[
4 |
3 |
7 |
3 |
分析:这6个算式都按照分数的四则混合运算的顺序进行计算,有括号的先计算括号内部的,再计算括号外部的,第⑥个式子再计算时多留心计算即可正确解答.
解答:解:①0.75÷0.25+
×
,
=
×4+
×
,
=3+
,
=3.5;
②(8.6×0.5-
)÷12,
=(4.3-3.1)÷12,
=1.2÷12,
=0.1;
③
÷[
-(
+
)],
=
÷[
-
],
=
÷
,
=
×
,
=1
;
④[800×(1+25%)-360×1.5]÷25%,
=[800×
-360×1.5]×4,
=[1000-540]×4,
=460×4,
=1840;
⑤15-[
+(2.5-
)]÷0.125,
=15-[
+
-
]÷
,
=15-[
+
-
]×8,
=15-
×8,
=15-12,
=3.
3 |
4 |
2 |
3 |
=
3 |
4 |
3 |
4 |
2 |
3 |
=3+
1 |
2 |
=3.5;
②(8.6×0.5-
31 |
10 |
=(4.3-3.1)÷12,
=1.2÷12,
=0.1;
③
39 |
10 |
15 |
4 |
4 |
3 |
1 |
6 |
=
39 |
10 |
15 |
4 |
3 |
2 |
=
39 |
10 |
9 |
4 |
=
39 |
10 |
4 |
9 |
=1
11 |
15 |
④[800×(1+25%)-360×1.5]÷25%,
=[800×
125 |
100 |
=[1000-540]×4,
=460×4,
=1840;
⑤15-[
4 |
3 |
7 |
3 |
=15-[
4 |
3 |
5 |
2 |
7 |
3 |
1 |
8 |
=15-[
8 |
6 |
15 |
6 |
14 |
6 |
=15-
3 |
2 |
=15-12,
=3.
点评:考查了运算定律与简便运算,四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算律简便计算.
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