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 350 and 252 is 98.

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 (which is (350+252)/2 = 301).

So, the percentage difference between 350 and 252 is:

(98/301) x 100% = 32.56%

Therefore, the percentage difference between 350 and 252 is 32.56%. This means that the two numbers differ by 32.56% of their average value.