题目内容
13×| 2 |
| 3 |
| 2 |
| 7 |
| 1 |
| 3 |
| 5 |
| 7 |
分析:根据乘法交换律、分配律及有理数乘法法则计算.
解答:解:13×
+0.34×
+
×(-13)+
×0.34
=13×
+
×13+0.34×
+
×0.34
=13×(
+
)+0.34×(
+
)
=13×1+0.34×1
=13+0.34
=13.34.
| 2 |
| 3 |
| 2 |
| 7 |
| 1 |
| 3 |
| 5 |
| 7 |
=13×
| 2 |
| 3 |
| 1 |
| 3 |
| 2 |
| 7 |
| 5 |
| 7 |
=13×(
| 2 |
| 3 |
| 1 |
| 3 |
| 2 |
| 7 |
| 5 |
| 7 |
=13×1+0.34×1
=13+0.34
=13.34.
点评:本题考查了有理数的混合运算,本题可以运用运算律简化计算.不为零的有理数相乘的法则:两数相乘,同号得正,异号得负,并把绝对值相乘.
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