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 205 and 180 is 25.

Next, we need to find the average of the two numbers. The average of 205 and 180 is (205+180)/2 = 192.5.

Now, we can calculate the percentage difference by dividing the absolute difference by the average and multiplying by 100. So, the percentage difference between 205 and 180 is (25/192.5) x 100 = 12.99%.

Therefore, the percentage difference between 205 and 180 is approximately 12.99%. This means that the second number (180) is about 12.99% less than the first number (205).