Answer:
0, 1 , 2, 3, 4, 5, 6, 7, 8, 9, A, B, 10, 11, 12, 13, 14, 15, 16, 17, 18
Step-By-Step Explanation:
i will go from 0 to 20:
0: 0
1: 1
2: 2
3: 3
4: 4
5: 5
6: 6
7: 7
8: 8
9: 9
10: A (10 is another 'digit')
11: B
12: 10 (12 = 1*12^1 + 0* 12^0)
13: 11 (13 = 1*12^1 + 1*12^0)
14: 12 (14 = 1*12^1 + 2*12^0)
15: 13
16: 14
17: 15
18: 16
19: 17
20: 18
Just remember to use the notation A and B after the digit nine, for example
22: 1A
23: 1B
24: 20
In other words, the answer is 0, 1 , 2, 3, 4, 5, 6, 7, 8, 9, A, B, 10, 11, 12, 13, 14, 15, 16, 17, 18