Answer:
In the range from 0 to 20 (inclusive), there are 21 values.
Explanation:
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20
If you include all the whole numbers starting from 0 up to and including 20, it results in a total of 21 values.