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.

Now, let's look at the numbers 50 and 66. 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 the sign. In this case, the absolute difference between 50 and 66 is 16.

Next, we need to find the average of the two numbers. The average of 50 and 66 is (50+66)/2 = 58.

Now, we can find the percentage difference by dividing the absolute difference by the average and multiplying by 100. So, the percentage difference between 50 and 66 is:

(16/58) x 100 = 27.59%

Therefore, the percentage difference between 50 and 66 is 27.59%. This means that 66 is 27.59% more than 50.