To find the percentage difference between two numbers, we first need to calculate the absolute difference between them. In this case, the absolute difference between 58 and 100 is 42 (100 - 58 = 42).

Next, we need to find the average of the two numbers. The average of 58 and 100 is (58 + 100) / 2 = 79.

Now, we can calculate the percentage difference by dividing the absolute difference by the average and multiplying by 100. So, the percentage difference between 58 and 100 is (42 / 79) x 100 = 53.16%.

This means that 58 is 53.16% less than 100, or that 100 is 53.16% more than 58.