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 304 and 212 is 92 (304 - 212 = 92).

Next, we need to find the average of the two numbers. The average of 304 and 212 is (304 + 212) / 2 = 258.

Now, we can calculate the percentage difference by dividing the absolute difference by the average and multiplying by 100. So, the percentage difference between 304 and 212 is (92 / 258) x 100 = 35.66%.

Therefore, the percentage difference between 304 and 212 is 35.66%. This means that the two numbers differ by 35.66% of their average value.