题目内容
(2013?宜丰县模拟)下面各题,怎样简便就怎样算.
| 19.98×37-199.8×1.9+1998×0.82 | 9999×7+1111×37 | ||||||||||||
[
|
(70+
|
分析:(1)19.98×37-199.8×1.9+1998×0.82,根据因数与积的变化规律将原式转化为:1998×0.37-1998×0.19+1998×0.82,然后运用乘法分配律进行简算;
(2)9999×7+1111×37,根据因数与积的变化规律将原式转化为:1111×63+1111×37,再运用乘法分配律进行简算;
(3)[
-(
-
)]×
,根据分数四则混合运算的顺序,按照分数四则运算的计算法则进行计算;
(4)(70+
)×
,转化为:(69+1+
)×
,运用乘法分配律进行简算.
(2)9999×7+1111×37,根据因数与积的变化规律将原式转化为:1111×63+1111×37,再运用乘法分配律进行简算;
(3)[
| 8 |
| 15 |
| 7 |
| 12 |
| 2 |
| 5 |
| 15 |
| 14 |
(4)(70+
| 1 |
| 68 |
| 1 |
| 69 |
| 1 |
| 68 |
| 1 |
| 69 |
解答:解:(1)19.98×37-199.8×1.9+1998×0.82,
=1998×0.37-1998×0.19+1998×0.82,
=1998×(0.37-0.19+0.82),
=1998×1,
=1998;
(2)9999×7+1111×37,
=1111×63+1111×37,
=1111×(63+37),
=1111×100,
=111100;
(3)[
-(
-
)]×
,
=[
-
]×
,
=
×
,
=
;
(4)(70+
)×
,
=:(69+1+
)×
,
=1+
+
×
,
=1+
×(1+
),
=1+
×
,
=1+
,
=1
;
=1998×0.37-1998×0.19+1998×0.82,
=1998×(0.37-0.19+0.82),
=1998×1,
=1998;
(2)9999×7+1111×37,
=1111×63+1111×37,
=1111×(63+37),
=1111×100,
=111100;
(3)[
| 8 |
| 15 |
| 7 |
| 12 |
| 2 |
| 5 |
| 15 |
| 14 |
=[
| 8 |
| 15 |
| 11 |
| 60 |
| 15 |
| 14 |
=
| 21 |
| 60 |
| 15 |
| 14 |
=
| 3 |
| 8 |
(4)(70+
| 1 |
| 68 |
| 1 |
| 69 |
=:(69+1+
| 1 |
| 68 |
| 1 |
| 69 |
=1+
| 1 |
| 69 |
| 1 |
| 68 |
| 1 |
| 69 |
=1+
| 1 |
| 69 |
| 1 |
| 68 |
=1+
| 1 |
| 69 |
| 69 |
| 68 |
=1+
| 1 |
| 68 |
=1
| 1 |
| 68 |
点评:此题考查的目的是掌握小数、分数四则混合运算的顺序以及计算法则,并且能够灵活运用简便方法进行计算.
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