题目内容
计算,能简算的写出简算过程.
(1)7.5÷
-2.5×
(2)3.5×
+5.5×80%+0.8
(3)24×[(1
-
)÷3]
(4)3.25-2.8×
+
×
÷0.1.
(1)7.5÷
2 |
5 |
5 |
2 |
(2)3.5×
4 |
5 |
(3)24×[(1
1 |
6 |
2 |
3 |
(4)3.25-2.8×
5 |
7 |
1 |
4 |
4 |
7 |
分析:(1)根据乘法分配律进行计算;
(2)根据乘法分配律进行计算;
(3)先算减法,再算除法,最后算乘法;
(4)先算乘法,再算除法;再算减法,最后算加法.
(2)根据乘法分配律进行计算;
(3)先算减法,再算除法,最后算乘法;
(4)先算乘法,再算除法;再算减法,最后算加法.
解答:解:
(1)7.5÷
-2.5×
,
=7.5×
-2.5×
,
=(7.5-2.5)×
,
=5×
,
=
;
(2)3.5×
+5.5×80%+0.8,
=3.5×0.8+5.5×0.8+0.8,
=(3.5+5.5+1)×0.8,
=10×0.8,
=8;
(3)24×[(1
-
)÷3],
=24×[
÷3],
=24×
,
=4;
(4)3.25-2.8×
+
×
÷0.1,
=3.25-2+
÷0.1,
=3.25-2+
,
=1.25+
,
=2
.
(1)7.5÷
2 |
5 |
5 |
2 |
=7.5×
5 |
2 |
5 |
2 |
=(7.5-2.5)×
5 |
2 |
=5×
5 |
2 |
=
25 |
2 |
(2)3.5×
4 |
5 |
=3.5×0.8+5.5×0.8+0.8,
=(3.5+5.5+1)×0.8,
=10×0.8,
=8;
(3)24×[(1
1 |
6 |
2 |
3 |
=24×[
1 |
2 |
=24×
1 |
6 |
=4;
(4)3.25-2.8×
5 |
7 |
1 |
4 |
4 |
7 |
=3.25-2+
1 |
7 |
=3.25-2+
10 |
7 |
=1.25+
10 |
7 |
=2
19 |
28 |
点评:此题主要考查分数、整数、小数的四则混合运算的运算顺序和应用运算定律进行简便计算.
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