题目内容
用简便方法计算.
(
+
-
)×24
2.5×3.2×12.5
÷23+
×
.
(
1 |
6 |
1 |
4 |
1 |
12 |
2.5×3.2×12.5
8 |
17 |
1 |
23 |
9 |
17 |
考点:分数的简便计算
专题:运算定律及简算
分析:(1)根据乘法分配律进行简算;
(2)根据乘法交换律和结合律进行简算;
(3)根据乘法分配律进行简算.
(2)根据乘法交换律和结合律进行简算;
(3)根据乘法分配律进行简算.
解答:
解:(1)(
+
-
)×24
=
×24+
×24-
×24
=4+6-2
=10-2
=8;
(2)2.5×3.2×12.5
=2.5×(4×0.8)×12.5
=(2.5×4)×(0.8×12.5)
=10×10
=100;
(3)
÷23+
×
=
×
+
×
=(
+
)×
=1×
=
.
1 |
6 |
1 |
4 |
1 |
12 |
=
1 |
6 |
1 |
4 |
1 |
12 |
=4+6-2
=10-2
=8;
(2)2.5×3.2×12.5
=2.5×(4×0.8)×12.5
=(2.5×4)×(0.8×12.5)
=10×10
=100;
(3)
8 |
17 |
1 |
23 |
9 |
17 |
=
8 |
17 |
1 |
23 |
1 |
23 |
9 |
17 |
=(
8 |
17 |
9 |
17 |
1 |
23 |
=1×
1 |
23 |
=
1 |
23 |
点评:此题主要考查分数、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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