题目内容
怎样算简便怎样算.
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1-30×(
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分析:(1)按照从左到右的顺序计算;
(2)先算小括号里面的减法,再算中括号里面的乘法,最后算括号外的除法;
(3)先算除法,再算减法,最后算加法;
(4)先运用乘法分配律简算,再算减法;
(5)先把除法变成乘法,再运用乘法分配律简算;
(6)先算小括号里面的加法,再算中括号里面的乘法,最后算括号外的除法.
(2)先算小括号里面的减法,再算中括号里面的乘法,最后算括号外的除法;
(3)先算除法,再算减法,最后算加法;
(4)先运用乘法分配律简算,再算减法;
(5)先把除法变成乘法,再运用乘法分配律简算;
(6)先算小括号里面的加法,再算中括号里面的乘法,最后算括号外的除法.
解答:解:(1)
÷
×
÷
,
=
×
×
,
=
×
,
=
;
(2)
÷[(
-
)×3],
=
÷[
×3],
=
÷
,
=
;
(3)
-
÷3+
,
=
-
+
,
=
+
,
=
;
(4)1-30×(
-
),
=1-[30×
-30×
],
=1-[6-5],
=1-1,
=0;
(5)
×
+
÷
,
=
×
+
×
,
=
×(
+
),
=
×1,
=
;
(6)
÷[(
+
)×
],
=
÷[
×
],
=
÷
,
=
.
| 2 |
| 3 |
| 4 |
| 5 |
| 1 |
| 8 |
| 3 |
| 4 |
=
| 5 |
| 6 |
| 1 |
| 8 |
| 4 |
| 3 |
=
| 5 |
| 48 |
| 4 |
| 3 |
=
| 5 |
| 36 |
(2)
| 7 |
| 20 |
| 5 |
| 6 |
| 2 |
| 3 |
=
| 7 |
| 20 |
| 1 |
| 6 |
=
| 7 |
| 20 |
| 1 |
| 2 |
=
| 7 |
| 10 |
(3)
| 3 |
| 4 |
| 3 |
| 4 |
| 9 |
| 25 |
=
| 3 |
| 4 |
| 1 |
| 4 |
| 9 |
| 25 |
=
| 1 |
| 2 |
| 9 |
| 25 |
=
| 43 |
| 50 |
(4)1-30×(
| 1 |
| 5 |
| 1 |
| 6 |
=1-[30×
| 1 |
| 5 |
| 1 |
| 6 |
=1-[6-5],
=1-1,
=0;
(5)
| 5 |
| 12 |
| 1 |
| 5 |
| 4 |
| 5 |
| 12 |
| 5 |
=
| 5 |
| 12 |
| 1 |
| 5 |
| 4 |
| 5 |
| 5 |
| 12 |
=
| 5 |
| 12 |
| 1 |
| 5 |
| 4 |
| 5 |
=
| 5 |
| 12 |
=
| 5 |
| 12 |
(6)
| 8 |
| 9 |
| 2 |
| 5 |
| 1 |
| 10 |
| 4 |
| 3 |
=
| 8 |
| 9 |
| 1 |
| 2 |
| 4 |
| 3 |
=
| 8 |
| 9 |
| 2 |
| 3 |
=
| 4 |
| 3 |
点评:此题主要考查分数的四则混合运算的运算顺序,以及应用运算定律进行简便计算的能力.
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