题目内容
简算
①5.4-1.82+4.6-0.18 | ②68×0.99 | ③
|
分析:①根据加法结合律和减法的性质简算;
②先把0.99分解成1-0.01,再运用乘法分配律简算;
③先算乘法,再根据减法的性质简算.
②先把0.99分解成1-0.01,再运用乘法分配律简算;
③先算乘法,再根据减法的性质简算.
解答:解:①5.4-1.82+4.6-0.18,
=(5.4+4.6)-(1.82+0.18),
=10-2,
=8;
②68×0.99,
=68×(1-0.01),
=68×1-68×0.01,
=68-0.68,
=67.32;
③
-
×
-
,
=
-
-
,
=
-(
+
),
=
-1,
=-
.
=(5.4+4.6)-(1.82+0.18),
=10-2,
=8;
②68×0.99,
=68×(1-0.01),
=68×1-68×0.01,
=68-0.68,
=67.32;
③
3 |
5 |
4 |
5 |
5 |
7 |
3 |
7 |
=
3 |
5 |
4 |
7 |
3 |
7 |
=
3 |
5 |
4 |
7 |
3 |
7 |
=
3 |
5 |
=-
2 |
5 |
点评:此题是考查四则混合运算,要仔细观察算式的特点,灵活运用一些定律进行简便计算.
练习册系列答案
相关题目