题目内容
下面各题怎样算简便就怎样算.
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(
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2-
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分析:(1)根据乘法交换律和结合律进行简算;
(2)根据乘法分配律进行简算;
(3)先算除法,再算加法;
(4)根据乘法分配律进行简算;
(5)先算除法,再算减法;
(6)先算小括号内的减法,再算乘法,最后算加法.
(2)根据乘法分配律进行简算;
(3)先算除法,再算加法;
(4)根据乘法分配律进行简算;
(5)先算除法,再算减法;
(6)先算小括号内的减法,再算乘法,最后算加法.
解答:解:(1)
×16×
,
=(
×
)×16,
=3×16,
=48;
(2)(
-
)×36,
=
×36-
×36,
=21-10,
=11;
(3)
+3÷
,
=
+6,
=6
;
(4)
×
+
÷
,
=
×
+
×
,
=
×(
+
),
=
×1,
=
;
(5)2-
÷
-
,
=2-
-
,
=2-(
+
),
=2-1,
=1;
(6)
+
×(
-0.25),
=
+
×
,
=
+
,
=
.
| 7 |
| 9 |
| 27 |
| 7 |
=(
| 7 |
| 9 |
| 27 |
| 7 |
=3×16,
=48;
(2)(
| 7 |
| 12 |
| 5 |
| 18 |
=
| 7 |
| 12 |
| 5 |
| 18 |
=21-10,
=11;
(3)
| 1 |
| 3 |
| 1 |
| 2 |
=
| 1 |
| 3 |
=6
| 1 |
| 3 |
(4)
| 7 |
| 18 |
| 1 |
| 4 |
| 3 |
| 4 |
| 18 |
| 7 |
=
| 7 |
| 18 |
| 1 |
| 4 |
| 3 |
| 4 |
| 7 |
| 18 |
=
| 7 |
| 18 |
| 1 |
| 4 |
| 3 |
| 4 |
=
| 7 |
| 18 |
=
| 7 |
| 18 |
(5)2-
| 3 |
| 8 |
| 7 |
| 16 |
| 1 |
| 7 |
=2-
| 6 |
| 7 |
| 1 |
| 7 |
=2-(
| 6 |
| 7 |
| 1 |
| 7 |
=2-1,
=1;
(6)
| 1 |
| 7 |
| 6 |
| 7 |
| 2 |
| 3 |
=
| 1 |
| 7 |
| 6 |
| 7 |
| 5 |
| 12 |
=
| 1 |
| 7 |
| 5 |
| 14 |
=
| 1 |
| 2 |
点评:四则混合运算,先弄清运算顺序,然后再进行计算,能简算的要简算.
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