To find the percentage difference between two numbers, we first need to find the absolute difference between them. In this case, the absolute difference between 30 and 80 is 50 (80 - 30 = 50).

Next, we need to find the average of the two numbers. The average of 30 and 80 is (30 + 80) / 2 = 55.

Now, we can find the percentage difference by dividing the absolute difference by the average and multiplying by 100. So, the percentage difference between 30 and 80 is (50 / 55) x 100 = 90.91%.

This means that the second number (80) is 90.91% greater than the first number (30).