问题 解答题
你认为怎样算简便就怎样算.
①(
1
6
+
1
5
)÷(
7
8
-
5
12

②[19.8-(4.9+9.8)]×(1÷0.01)
③155×360×77÷90÷11÷31
④1÷28×72-27×
1
28
-17÷28.
答案

①(

1
6
+
1
5
)÷(
7
8
-
5
12
),

=

11
30
÷
11
24

=

11
30
×
24
11

=

4
5

②[19.8-(4.9+9.8)]×(1÷0.01),

=[19.8-14.7]×100,

=5.1×100,

=510;

③155×360×77÷90÷11÷31,

=(155÷31)×(360÷90)×(77÷11),

=5×4×7,

=140;

④1÷28×72-27×

1
28
-17÷28,

=

1
28
×72-27×
1
28
-17×
1
28

=

1
28
×(72-27-17),

=

1
28
×28,

=1.

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