题目内容
(2011?建华区)用简便方法计算.
| 87×101 |
| ||||||||
| 13.55-3.76+5.45-7.24 | 24×(
|
分析:(1)把101看作100+1,运用乘法分配律简算;
(2)(3)运用加法交换律与结合律简算;
(4)运用乘法分配律简算.
(2)(3)运用加法交换律与结合律简算;
(4)运用乘法分配律简算.
解答:解:(1)87×101,
=87×(100+1),
=87×100+87,
=8700+87,
=8787;
(2)
+
+
+
,
=(
+
)+(
+
),
=2+1,
=3;
(3)13.55-3.76+5.45-7.24,
=(13.55+5.45)-(3.76+7.24),
=19-11,
=8;
(4)24×(
+
+
),
=24×
+24×
+24×
,
=10+1+9,
=20.
=87×(100+1),
=87×100+87,
=8700+87,
=8787;
(2)
| 6 |
| 7 |
| 7 |
| 9 |
| 8 |
| 7 |
| 2 |
| 9 |
=(
| 6 |
| 7 |
| 8 |
| 7 |
| 7 |
| 9 |
| 2 |
| 9 |
=2+1,
=3;
(3)13.55-3.76+5.45-7.24,
=(13.55+5.45)-(3.76+7.24),
=19-11,
=8;
(4)24×(
| 5 |
| 12 |
| 1 |
| 24 |
| 3 |
| 8 |
=24×
| 5 |
| 12 |
| 1 |
| 24 |
| 3 |
| 8 |
=10+1+9,
=20.
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.
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