题目内容
计算下面各题,注意使用简便算法.
(
-
)÷
÷7+
×
(
+
+
)÷
÷(
-
×
)
(
| 2 |
| 3 |
| 1 |
| 4 |
| 5 |
| 6 |
| 8 |
| 13 |
| 1 |
| 7 |
| 6 |
| 13 |
(
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 6 |
| 1 |
| 12 |
| 6 |
| 5 |
| 1 |
| 2 |
| 4 |
| 7 |
| 7 |
| 12 |
分析:(1)(4)按运算顺序进行计算,即先算括号里面的运算,再算括号外面的运算;
(2)(3)运用乘法分配律进行计算比较简便.
(2)(3)运用乘法分配律进行计算比较简便.
解答:解:(1)(
-
)÷
=(
-
)÷
=
×
=
;
(2)
÷7+
×
=
×
+
×
=
×(
+
)
=
×
=
;
(3)(
+
+
)÷
=
×12+
×12+
×12
=4+3+2
=9;
(4)
÷(
-
×
)
=
÷(
-
)
=
÷
=
.
| 2 |
| 3 |
| 1 |
| 4 |
| 5 |
| 6 |
=(
| 8 |
| 12 |
| 3 |
| 12 |
| 5 |
| 6 |
=
| 5 |
| 12 |
| 6 |
| 5 |
=
| 1 |
| 2 |
(2)
| 8 |
| 13 |
| 1 |
| 7 |
| 6 |
| 13 |
=
| 8 |
| 13 |
| 1 |
| 7 |
| 1 |
| 7 |
| 6 |
| 13 |
=
| 1 |
| 7 |
| 8 |
| 13 |
| 6 |
| 13 |
=
| 1 |
| 7 |
| 14 |
| 13 |
=
| 2 |
| 13 |
(3)(
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 6 |
| 1 |
| 12 |
=
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 6 |
=4+3+2
=9;
(4)
| 6 |
| 5 |
| 1 |
| 2 |
| 4 |
| 7 |
| 7 |
| 12 |
=
| 6 |
| 5 |
| 1 |
| 2 |
| 1 |
| 3 |
=
| 6 |
| 5 |
| 1 |
| 6 |
=
| 36 |
| 5 |
点评:此题是考查四则混合运算,要仔细观察算式的特点,灵活运用一些定律进行简便计算.
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| ( | ||
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