adding with regrouping

3:56

4:35

11:20

7:59

5:17

3:19

5:51

9:11

3:04

6:26

9:31

11:42

5:41

7:09

2:40

2:42

9:54

6:45

15:37

1:10

2:00

2:47

2:31

3:16

5:43

2:20

2:26

1:15

3:40

2:16

7:32

2:57

5:07

3:47

3:15

2:46

3:48

4:13

2:24

6:41

4:12

13:05

00:59

10:15

8:08

6:33

9:10

5:36

3:25

13:44

3:20

6:26

9:54

2:24

7:32

2:31

2:45

8:38

8:17

9:29