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 180 and 64 is 116.

Next, we need to find what percentage this absolute difference is of the original number. To do this, we divide the absolute difference by the average of the two numbers (in this case, (180+64)/2 = 122), and then multiply by 100 to get the percentage.

So, the percentage difference between 180 and 64 is:

(116/122) x 100 = 95.08%

This means that 95.08% is the percentage by which 180 differs from 64.