Numbers

9 + a number is that number.

9 + 1 = 10 = 1
9 + 2 = 11 = 2
9 + 9 = 18 = 9
9 + 14 (5) = 23 = 5

On the hour of a clock and opposite is:

12:30 = 6
1:35 = 9
2:40 = 6
3:45 = 12 = 3
4:50 = 9
5:55 = 15 = 6
6:00 = 6
7:05 = 12 = 3
8:10 = 9
9:15 = 15 = 6
10:20 = 3
11:25 = 9

6, 9, 6, 3, 9, 6, 6, 3, 9, 6, 3, 9

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 = 45 = 9

(skips 0)

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 = 55 = 10 = 1

(skips 2)

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 (2) = 66 = 12 = 3

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 (1) + 11 (2) + 12 (3) = 78 = 15 = 6

9 x 1 = 9
9 x 2 = 18 = 9
9 x 3 = 27 = 9
9 x 4 = 36 = 9
9 x 5 = 45 = 9 (reverse)
9 x 6 = 54 = 9 (reverse)
9 x 7 = 63 = 9
9 x 8 = 72 = 9
9 x 9 = 81 = 9
9 x 10 = 90 = 9
9 x 11 = 99 = 18 = 9
9 x 12= 108 = 9