(共22张PPT)
加进来,减出去
5
10
15
20
+
=
8
5
13
-
=
8
5
13
5
10
15
20
+
=
8
5
13
+
=
7
5
12
5
10
15
20
-
=
7
5
12
5
10
15
20
+
=
7
5
12
+
=
-
=
6
5
11
6
5
11
5
10
15
20
+
=
-
=
8
7
15
8
7
15
5
10
15
20
+
=
-
=
9
3
12
9
3
12
5
10
15
20
+
=
-
=
5
6
5
6
11
11
+
=
-
=
+
=
-
=
+
=
-
=
+
=
-
=
8
4
8
4
12
12
6
7
6
7
13
13
3
9
3
9
12
12
9
5
9
5
14
14
-
=
8
4
12
+
=
8
4
12
-
=
6
7
13
+
=
6
7
13
-
=
3
9
12
+
=
3
9
12
-
=
9
5
14
+
=
9
5
14
+
=
+
=
+
=
+
=
-
=
5
6
11
5
6
11
-
=
7
9
16
7
9
16
-
=
8
7
15
8
7
15
-
=
4
9
13
4
9
13
-
=
9
8
17
-
=
8
6
14
+
=
+
=
+
=
9
8
17
+
=
8
6
14
-
=
6
7
13
6
7
13
-
=
3
8
11
3
8
11
8
6
14
8
6
14
14
14
8
6
8
6
9
6
15
6
9
15
15
15
9
6
6
9
+
+
-
-
=
=
=
=
1
2
3
5
8
13