精英家教网 > 小学数学 > 题目详情
7
13
-0.4+
6
13
-
3
5
分析:根据本题的特征,要把0.4变成
2
5
,然后再利用加法的结合律和减法的性质,即可解答.
解答:解:
7
13
-0.4+
6
13
-
3
5

=
7
13
-
2
5
+
6
13
-
3
5

=(
7
13
+
6
13
)-(
2
5
+
3
5
),
=1-1,
=0.
点评:在进行四则混合运算时要根据题的特征,灵活地把一个或几个数合理的变形会使计算简便,但变形的前提是数的大小不能变化.
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