题目内容
怎样简便怎样算
×
+25%×
+0.25×
×
×
-
×25%+
×4
.
3 |
7 |
1 |
4 |
2 |
7 |
1 |
7 |
4 |
5 |
4 |
7 |
5 |
4 |
1 |
2 |
2 |
9 |
3 |
4 |
1 |
2 |
考点:运算定律与简便运算
专题:运算定律及简算
分析:(1)通过数字转化,运用乘法分配律简算.
(2)先运用乘法交换律与结合律简算,最后算减法;
(3)把百分数化为分数,先算乘法,再算加法.
(2)先运用乘法交换律与结合律简算,最后算减法;
(3)把百分数化为分数,先算乘法,再算加法.
解答:
解:(1)
×
+25%×
+0.25×
=
×
+
×
+
×
=
×(
+
+
)
=
×
=
(2)
×
×
-
=(
×
)×
-
=
-
=
(3)
×25%+
×4
=
×
+
×
=
+
=
3 |
7 |
1 |
4 |
2 |
7 |
1 |
7 |
=
3 |
7 |
1 |
4 |
1 |
4 |
2 |
7 |
1 |
4 |
1 |
7 |
=
1 |
4 |
3 |
7 |
2 |
7 |
1 |
7 |
=
1 |
4 |
6 |
7 |
=
3 |
14 |
(2)
4 |
5 |
4 |
7 |
5 |
4 |
1 |
2 |
=(
4 |
5 |
5 |
4 |
4 |
7 |
1 |
2 |
=
4 |
7 |
1 |
2 |
=
1 |
14 |
(3)
2 |
9 |
3 |
4 |
1 |
2 |
=
2 |
9 |
1 |
4 |
3 |
4 |
9 |
2 |
=
1 |
18 |
27 |
8 |
=
247 |
72 |
点评:考查了分数的四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.
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