+
0
1
2
3
4
5
6
7
8
9
10
0
0
1
2
3
4
5
6
7
8
9
10
1
1
2
3
4
5
6
7
8
9
10
11
2
2
3
4
5
6
7
8
9
10
11
12
3
3
4
5
6
7
8
9
10
11
12
13
4
4
5
6
7
8
9
10
11
12
13
14
5
5
6
7
8
9
10
11
12
13
14
15
6
6
7
8
9
10
11
12
13
14
15
16
7
7
8
9
10
11
12
13
14
15
16
17
8
8
9
10
11
12
13
14
15
16
17
18
9
9
10
11
12
13
14
15
16
17
18
19
10
10
11
12
13
14
15
16
17
18
19
20
Why does
4
+
4
=
8
?
Let's start at
4
.
Next, let's count
4
times.
Ready? ...
4
,
5
1
,
6
2
,
7
3
,
8
4
.
That's why
4
+
4
=
8
.
Mathgrow
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
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