题目内容
能简算的要简算: (1)47.5-4.25-15.75 |
(2)91-91÷13 | (3)
| ||||||||||||||
(4)
|
(5)125×3.2×0.25 | (6)
|
分析:算式(2)(4)(6)根据四则混合运算的运算法则计算即可:先算乘除,再算加减,有括号的要先算括号里面的.
算式(1)可根据一个数减两个数等于减去这两个数的和的减法性质进行计算;
算式(3)可以根据乘法分配律进计算;
算式(5)可先将3.2拆分为0.8×4后再根据乘法结合律进行计算.
算式(1)可根据一个数减两个数等于减去这两个数的和的减法性质进行计算;
算式(3)可以根据乘法分配律进计算;
算式(5)可先将3.2拆分为0.8×4后再根据乘法结合律进行计算.
解答:解:(1)47.5-4.25-15.75
=47.5-(4.25+15.75),
=47.5-20,
=27.5;
(2)91-91÷13
=91-7,
=84;
(3)
×16.3-2.3÷
=
×16.3-2.3×
,
=(16.3-2.3)×
,
=14×
,
=10;
(4)
÷
×
=
×2×
,
=
;
(5)125×3.2×0.25,
=125×0.8×4×0.25,
=(125×0.8)×(4×0.25),
=100×1,
=100;
(6)
÷[
×(
+
)],
=
÷[
×
],
=
×
,
=
.
=47.5-(4.25+15.75),
=47.5-20,
=27.5;
(2)91-91÷13
=91-7,
=84;
(3)
5 |
7 |
7 |
5 |
=
5 |
7 |
5 |
7 |
=(16.3-2.3)×
5 |
7 |
=14×
5 |
7 |
=10;
(4)
3 |
4 |
1 |
2 |
2 |
5 |
=
3 |
4 |
2 |
5 |
=
3 |
5 |
(5)125×3.2×0.25,
=125×0.8×4×0.25,
=(125×0.8)×(4×0.25),
=100×1,
=100;
(6)
9 |
20 |
1 |
2 |
2 |
5 |
4 |
5 |
=
9 |
20 |
1 |
2 |
6 |
5 |
=
9 |
20 |
5 |
3 |
=
3 |
4 |
点评:完成本题时要注意分析式中数据的特点及内在联系,然后选择合适的方法进计简便计算.
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