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 129 and 79 is 50 (129 - 79 = 50).

Next, we need to find the average of the two numbers. The average of 129 and 79 is (129 + 79) / 2 = 104.

Now, we can calculate the percentage difference by dividing the absolute difference by the average and multiplying by 100. So, the percentage difference between 129 and 79 is (50 / 104) x 100 = 48.08%.

This means that the second number (79) is 48.08% less than the first number (129). Alternatively, we can say that the first number (129) is 48.08% more than the second number (79).