Calculating the difference between three numbers in percentage is a straightforward process. Here are the steps you can follow:

1. Determine the largest and smallest numbers among the three amounts.
2. Subtract the smallest number from the largest number to find the difference.
3. Divide the difference by the smallest number.
4. Multiply the result by 100 to get the percentage difference.

For example, let's say we have three numbers: 10, 20, and 30.

1. The largest number is 30 and the smallest number is 10.

2. The difference between 30 and 10 is 20.

3. Divide 20 by 10 to get 2.

4. Multiply 2 by 100 to get the percentage difference, which is 200%.

Therefore, the percentage difference between 10, 20, and 30 is 200%. This means that the largest number (30) is 200% greater than the smallest number (10).