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 255 and 300 is 45 (300 - 255 = 45).

Next, we need to find the average of the two numbers. The average of 255 and 300 is (255 + 300) / 2 = 277.5.

Now, we can find the percentage difference by dividing the absolute difference by the average and multiplying by 100. So, the percentage difference between 255 and 300 is (45 / 277.5) x 100 = 16.22%.

This means that the second number (300) is 16.22% greater than the first number (255).