问题 解答题
(1)计算:3
3
7
-(-1
4
21
)

(2)计算:(-1
1
2
)3×(-
1
3
3
4
答案

(1)3

3
7
-(-1
4
21
),

=3

3
7
+1
4
21

=3

9
21
+1
4
21

=4

13
21

(2)(-1

1
2
3×(-
1
3
÷
3
4

=(-

3
2
3×(-
1
3
)×
4
3

=(-

27
8
)×(-
1
3
)×
4
3

=

27
8
×
1
3
×
4
3

=1

1
2

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