When A combination lock uses 3 numbers each of which can be 0 to 20. If there are no restrictions on the numbers how many possible combinations are available?

For a combination lock using 3 numbers, each ranging from 0 to 20, there are 21 possible choices for each number (including 0). Therefore, the total number of combinations can be calculated as 21 (choices for the first number) × 21 (choices for the second number) × 21 (choices for the third number), which equals 21^3. This results in 9,261 possible combinations.