To understand the percentage difference between two numbers, we first need to know what percentage means. Percentage is a way of expressing a number as a fraction of 100. For example, 50% means 50 out of 100 or 0.5 as a decimal.

Now, let's look at the two numbers given in the problem - 285 and 300. To find the percentage difference between them, we need to first find the absolute difference between the two numbers. Absolute difference means the difference without considering whether the numbers are positive or negative.

So, the absolute difference between 285 and 300 is:

300 - 285 = 15

Now, we need to find the percentage difference between these two numbers. To do this, we divide the absolute difference by the average of the two numbers and then multiply by 100. The formula for percentage difference is:

Percentage Difference = (Absolute Difference / Average of the two numbers) x 100

So, the average of 285 and 300 is:

(285 + 300) / 2 = 292.5

Now, we can plug in the values in the formula:

Percentage Difference = (15 / 292.5) x 100

Percentage Difference = 5.13%

Therefore, the percentage difference between 285 and 300 is 5.13%. This means that 300 is 5.13% more than 285.