题目内容
(54+
|
105×13-1890÷18 | 36÷[(
| ||||||
9.25×9.9+92.5% | 258×852852-852×258258. |
分析:(1)把÷9改写成×
,进而运用乘法分配律简算;
(2)按照先算乘除法,再算减法的顺序计算;
(3)运用乘法分配律计算中括号中的运算,再计算中括号外面的除法;
(4)把92.5%改写成0.925,把9.25×9.9改写成0.925×99,逆用乘法分配律简算;
(5)把258×852852-852×258258改写成258×852×1001-852×258×1001,计算得0.
1 |
9 |
(2)按照先算乘除法,再算减法的顺序计算;
(3)运用乘法分配律计算中括号中的运算,再计算中括号外面的除法;
(4)把92.5%改写成0.925,把9.25×9.9改写成0.925×99,逆用乘法分配律简算;
(5)把258×852852-852×258258改写成258×852×1001-852×258×1001,计算得0.
解答:解:(1)(54+
)÷9,
=(54+
)×
,
=54×
+
×
,
=6+
,
=6
;
(2)105×13-1890÷18,
=1365-105,
=1260;
(3)36÷[(
-
)×3],
=36÷[
×3-
×3],
=36÷
,
=24;
(4)9.25×9.9+92.5%,
=0.925×99+0.925,
=0.925×(99+1),
=0.925×100,
=92.5;
(5)258×852852-852×258258,
=258×852×1001-852×258×1001,
=0.
9 |
13 |
=(54+
9 |
13 |
1 |
9 |
=54×
1 |
9 |
9 |
13 |
1 |
9 |
=6+
1 |
13 |
=6
1 |
13 |
(2)105×13-1890÷18,
=1365-105,
=1260;
(3)36÷[(
5 |
6 |
1 |
3 |
=36÷[
5 |
6 |
1 |
3 |
=36÷
3 |
2 |
=24;
(4)9.25×9.9+92.5%,
=0.925×99+0.925,
=0.925×(99+1),
=0.925×100,
=92.5;
(5)258×852852-852×258258,
=258×852×1001-852×258×1001,
=0.
点评:此题考查了四则混合运算、运算定律与简便运算,在计算时,要注意运算顺序和运算法则,并灵活运用所学的运算定律进行简便计算.
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