题目内容
用适当的方法计算下列各题.
18÷
×
÷9
×
+
×
+
66×
.
18÷
| 8 |
| 13 |
| 8 |
| 13 |
| 5 |
| 8 |
| 5 |
| 12 |
| 5 |
| 12 |
| 7 |
| 8 |
| 5 |
| 8 |
66×
| 21 |
| 88 |
考点:分数的简便计算
专题:运算定律及简算
分析:(1)先把除法变成乘法,再运用乘法分配律简算;
(2)先运用乘法分配律简算,再算最后的家加法;
(3)直接约分求解即可.
(2)先运用乘法分配律简算,再算最后的家加法;
(3)直接约分求解即可.
解答:
解:(1)18÷
×
÷9
=18×
×
×
=(18×
)×(
×
)
=2×1
=2;
(2)
×
+
×
+
=
×(
+
)+
=
×
+
=
+
=
;
(3)66×
=
=
.
| 8 |
| 13 |
| 8 |
| 13 |
=18×
| 13 |
| 8 |
| 8 |
| 13 |
| 1 |
| 9 |
=(18×
| 1 |
| 9 |
| 13 |
| 8 |
| 8 |
| 13 |
=2×1
=2;
(2)
| 5 |
| 8 |
| 5 |
| 12 |
| 5 |
| 12 |
| 7 |
| 8 |
| 5 |
| 8 |
=
| 5 |
| 12 |
| 5 |
| 8 |
| 7 |
| 8 |
| 5 |
| 8 |
=
| 5 |
| 12 |
| 12 |
| 8 |
| 5 |
| 8 |
=
| 5 |
| 8 |
| 5 |
| 8 |
=
| 5 |
| 4 |
(3)66×
| 21 |
| 88 |
=
=
| 63 |
| 4 |
点评:本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
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