题目内容
怎样简便怎样算.
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(
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100×
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分析:(1)根据乘法交换律进行计算;
(2)根据乘法结合律进行计算;
(3)根据乘法分配律进行计算;
(4)根据乘法分配律进行计算;
(5)根据乘法分配律进行计算;
(6)根据乘法结合律进行计算.
(2)根据乘法结合律进行计算;
(3)根据乘法分配律进行计算;
(4)根据乘法分配律进行计算;
(5)根据乘法分配律进行计算;
(6)根据乘法结合律进行计算.
解答:解:
(1)
×
×6,
=
×6×
,
=5×
,
=
;
(2)
×
×
,
=
×(
×
),
=
×
,
=
;
(3)(
+
)×14,
=
×14+
×14,
=6+7,
=13;
(4)
×
+
×
,
=
×(
+
),
=
×1,
=
;
(5)100×
,
=(99+1)×
,
=99×
+1×
,
=2+
,
=2
;
(6)
×
×
×
,
=(
×
)×(
×
),
=
×
,
=
.
(1)
| 5 |
| 6 |
| 7 |
| 25 |
=
| 5 |
| 6 |
| 7 |
| 25 |
=5×
| 7 |
| 25 |
=
| 7 |
| 5 |
(2)
| 2 |
| 5 |
| 3 |
| 14 |
| 2 |
| 3 |
=
| 2 |
| 5 |
| 3 |
| 14 |
| 2 |
| 3 |
=
| 2 |
| 5 |
| 1 |
| 7 |
=
| 2 |
| 35 |
(3)(
| 3 |
| 7 |
| 1 |
| 2 |
=
| 3 |
| 7 |
| 1 |
| 2 |
=6+7,
=13;
(4)
| 5 |
| 8 |
| 5 |
| 8 |
| 5 |
| 8 |
| 3 |
| 8 |
=
| 5 |
| 8 |
| 5 |
| 8 |
| 3 |
| 8 |
=
| 5 |
| 8 |
=
| 5 |
| 8 |
(5)100×
| 2 |
| 99 |
=(99+1)×
| 2 |
| 99 |
=99×
| 2 |
| 99 |
| 2 |
| 99 |
=2+
| 2 |
| 99 |
=2
| 2 |
| 99 |
(6)
| 5 |
| 14 |
| 7 |
| 25 |
| 5 |
| 8 |
| 2 |
| 3 |
=(
| 5 |
| 14 |
| 7 |
| 25 |
| 5 |
| 8 |
| 2 |
| 3 |
=
| 1 |
| 10 |
| 5 |
| 12 |
=
| 1 |
| 24 |
点评:四则运算,先弄清运算顺序,然后再进一步计算即可,能简算的要简算.
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