(1)17×
11
23 +17÷
23
12
=17×
11
23 +17×
12
23
=17×(
11
23 +
12
23 )
=17×1
=17
(2)
2
5 ÷(
3
4 +
2
5 )
=
2
5 ÷
23
20
=
2
5 ×
20
23
=
8
23
(3)(
5
6 -
2
3 )×
9
10
=
1
6 ×
9
10
=
3
20
(1)17×
11
23 +17÷
23
12
=17×
11
23 +17×
12
23
=17×(
11
23 +
12
23 )
=17×1
=17
(2)
2
5 ÷(
3
4 +
2
5 )
=
2
5 ÷
23
20
=
2
5 ×
20
23
=
8
23
(3)(
5
6 -
2
3 )×
9
10
=
1
6 ×
9
10
=
3
20