题目内容
(2004?长汀县)用简便方法计算(要写出简算过程)
①475-198
②0.7+3.9+4.3+6.1
③(
+
)×15.
①475-198
②0.7+3.9+4.3+6.1
③(
1 |
3 |
2 |
5 |
分析:①把198看做200-2,运用减法的性质和加法结合律简算;
②运用加法交换律与结合律简算;
③运用乘法分配律简算.
②运用加法交换律与结合律简算;
③运用乘法分配律简算.
解答:解:①475-198,
=475-(200-2),
=475-200+2,
=275+2,
=277;
②0.7+3.9+4.3+6.1,
=(0.7+4.3)+(3.9+6.1),
=5+10,
=15;
③(
+
)×15,
=
×15+
×15,
=5+6,
=11.
=475-(200-2),
=475-200+2,
=275+2,
=277;
②0.7+3.9+4.3+6.1,
=(0.7+4.3)+(3.9+6.1),
=5+10,
=15;
③(
1 |
3 |
2 |
5 |
=
1 |
3 |
2 |
5 |
=5+6,
=11.
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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