题目内容
“口算”对对碰
+
=
2+
=
+
+
=
3-
=
+
=
-
-
=
3 |
4 |
1 |
4 |
2+
4 |
9 |
1 |
7 |
3 |
7 |
5 |
7 |
3-
3 |
4 |
2 |
3 |
1 |
6 |
5 |
16 |
1 |
16 |
1 |
16 |
分析:根据分数加减法的计算方法进行计算.
解答:解:
+
=1
2+
=2
+
+
=
3-
=2
+
=
-
-
=
.
3 |
4 |
1 |
4 |
2+
4 |
9 |
4 |
9 |
1 |
7 |
3 |
7 |
5 |
7 |
9 |
7 |
3-
3 |
4 |
1 |
4 |
2 |
3 |
1 |
6 |
5 |
6 |
5 |
16 |
1 |
16 |
1 |
16 |
3 |
16 |
点评:口算时,注意运算符号和数据,然后再进一步计算.

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