问题 解答题
62.8×19-8×62
4
5
-62
4
5

1800-1350÷18×6;
(2
5
12
+1
5
8
+2
7
12
+3.375)×
3
20

1.9-1.9×(1.9-1.9).
答案

(1)62.8×19-8×62

4
5
-62
4
5

=62.8×19-8×62.8-62.8,

=62.8×(19-8-1),

=62.8×10,

=628;

(2)1800-1350÷18×6,

=1800-1350÷9÷2×6,

=1800-75×6,

=1800-450,

=1350;

(3)(2

5
12
+1
5
8
+2
7
12
+3.375)×
3
20

=[(2

5
12
+2
7
12
)+(1.625+3.375)]×
3
20

=[5+5]×

3
20

=10×

3
20

=1.5;

(4)1.9-1.9×(1.9-1.9),

=1.9-1.9×0,

=1.9-0,

=1.9.

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